TAC I/A Series MicroNet BACnet
Wiring, Networking, and
Best Practices Guide
TAC I/A Series MicroNet BACnet
Wiring, Networking, and
Best Practices Guide
Printed in U.S.A.
06-14
F-27360-11
All brand names, trademarks and registered trademarks are the property of their respective owners. Information contained within this document is subject to change
without notice.
Schneider Electric 1-888-444-1311
F-27360-11
www.schneider-electric.com
June 2014 tl
© 2014 Schneider Electric. All rights reserved.
Distributed, manufactured, and sold by Schneider Electric.
I/A Series trademarks are owned by Invensys Systems, Inc. and are
used on this product under master license from Invensys. Invensys does
not manufacture this product or provide any product warranty or support.
For service, support, and warranty information, contact
Schneider Electric.
Table of Contents
Preface
Purpose of this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Applicable Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
Related Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Conventions Used in this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii
Acrobat (PDF) Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii
Abbreviations and Terms Used in this Manual . . . . . . . . . . . . . . .xii
Manual Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii
Chapter 1
I/A Series BACnet Hardware
MicroNet BACnet Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Common Controller Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BACnet Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
MNB-300 Unitary Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
MNB-V1, MNB-V2 VAV Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . 5
MNB-70 Zone Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MNB-1000 Plant Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MNB-1000-15 Remote I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Input and Output Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Universal Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Universal Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Digital Outputs, Triac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
20 Vdc Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Inputs from MN-Sx MicroNet Sensor . . . . . . . . . . . . . . . . . . . . . . 19
Velocity Pressure Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
MicroNet Digital Wall Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Common Sensor Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Keypad Icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
LCD Icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Diagnostic Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Communications Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Intermixing of Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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Sensor Link (S-Link) Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
MicroNet MS/TP Network Wiring . . . . . . . . . . . . . . . . . . . . . . . . . 26
ADI and Remote I/O Network Wiring . . . . . . . . . . . . . . . . . . . . . . 27
I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Power Supply Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Sensor Link (S-Link) Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
MicroNet MS/TP Network Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Cable Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Approved Cable Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
ADI and Remote I/O Module Network Wiring . . . . . . . . . . . . . . . . . . 31
Wiring Specifications for ADI or Remote I/O . . . . . . . . . . . . . . . . 31
I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Power Supply Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Chapter 2
Networking Practices
Introduction to BACnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Architecture Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
MS/TP Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Physical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Number of Connected Devices . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Logical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Addressing Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Limits to Number of Polled Points . . . . . . . . . . . . . . . . . . . . . . . . 43
Limits to Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Connection to an MS/TP Network . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Remote I/O Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Physical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Number of Connected Devices . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Logical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Addressing Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Increased I/O Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
MS/TP Network Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Master and Slave Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Physical Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Required Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
MS/TP Address for BACnet Tools . . . . . . . . . . . . . . . . . . . . . . . . 47
Other Network Setup Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Port Bridging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Single Path to Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Routers and Network Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Network Setup Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Physical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Set the DIP Switches on the Controllers . . . . . . . . . . . . . . . . . . . . . . 52
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MS/TP Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote I/O Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power on the MNB-xxxx Devices . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commission UNCs and ENCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commission the Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 3
52
52
52
52
52
Checkout and Troubleshooting
Mechanical Hardware Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communications Hardware Checkout . . . . . . . . . . . . . . . . . . . . . . . . .
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Field-replaceable Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
55
62
62
BACnet Best Practices
I/A Series MicroNet BACnet System Architecture Overview . . . . . . . .
MS/TP Network Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Master-Slave Token Passing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BACnet Rules that Must be Followed . . . . . . . . . . . . . . . . . . . . . . . . . .
General BACnet Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
No Duplicate Device Instances . . . . . . . . . . . . . . . . . . . . . . . . . .
No Duplicate Object Identifiers within a Device . . . . . . . . . . . . . .
No Duplicate Network Numbers . . . . . . . . . . . . . . . . . . . . . . . . . .
Devices on a Network Must Share a Single Network Number . . .
One Communication Path Only . . . . . . . . . . . . . . . . . . . . . . . . . .
MS/TP Network Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
No Duplicate Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Install Terminators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use Proper Communication Cable . . . . . . . . . . . . . . . . . . . . . . .
Bond the Shield to a Proper Ground . . . . . . . . . . . . . . . . . . . . . .
BACnet Best Practice Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selection of WP Tech Object Type for BACnet . . . . . . . . . . . . . . . .
MS/TP Network Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Keep Exposed Communication Conductors Short . . . . . . . . . . . .
Do Not Nick the Insulation When Removing the Cable Sheath . .
Make Low Resistance Terminations . . . . . . . . . . . . . . . . . . . . . .
Address Devices Consecutively . . . . . . . . . . . . . . . . . . . . . . . . . .
A Router’s Address Should Be 0 (Zero) . . . . . . . . . . . . . . . . . . . .
Few Controllers Per Network . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use BACnet/IP for the MNB-1000 . . . . . . . . . . . . . . . . . . . . . . . .
Use Higher Baud Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use Auto-baud to Change Baud Rate . . . . . . . . . . . . . . . . . . . . .
Add a Controller as MS/TP Slave After a Failed Upgrade . . . . . .
Power the Controllers Properly . . . . . . . . . . . . . . . . . . . . . . . . . .
Repeaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set MaxInfoFrames to Value Greater Than 1 . . . . . . . . . . . . . . .
Set the MaxMaster Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tuning the MaxMaster Property . . . . . . . . . . . . . . . . . . . . . . . . . .
Discussion of Joining Token Passing . . . . . . . . . . . . . . . . . . . . .
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Understanding the Transmit and Receive Data LEDs on MS/TP Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
BACnet/IP Network Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Set the gateway address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Use BBMDs When Needed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
BACnet/IP Through a NAT Router . . . . . . . . . . . . . . . . . . . . . . . . 81
BACnet Ethernet Network Guidelines . . . . . . . . . . . . . . . . . . . . . . . . 81
BACnet/Ethernet is Not Routed . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Do Not Leave BACnet/Ethernet Enabled if Not Used . . . . . . . . . 81
BACnet Guidelines for UNCs and ENCs . . . . . . . . . . . . . . . . . . . . . 81
Fewer Points Equals Better Performance . . . . . . . . . . . . . . . . . . 81
Use Poll On Demand for Schedules, Alarms, and Trends . . . . . . 82
Delete Unused Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Keep the UNC or ENC Routing . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Keep the Processor Idle Time Above 20% . . . . . . . . . . . . . . . . . . 83
UNC and ENC Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Use COV Subscription for Slowly Changing Points . . . . . . . . . . . 83
Do Not Use COV for Priority Type Points . . . . . . . . . . . . . . . . . . . 84
Tuning Policy for ENC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
General BACnet Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Consider Network Design Carefully . . . . . . . . . . . . . . . . . . . . . . . 84
Remote Connectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
BBMDs–
Connecting BACnet/IP Devices on Different Subnets . . . . . . . . . . . 85
Setup of BBMD in the MNB-1000 . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Use of VPN for Off-site Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Using a BBMD with an NAT Router . . . . . . . . . . . . . . . . . . . . . . . . . 90
WP Tech/WPCT BACnet/IP Remote Connection Setup . . . . . . . . . 91
Performance Improvements for MS/TP . . . . . . . . . . . . . . . . . . . . . . . . . 94
Implementing Performance Improvements . . . . . . . . . . . . . . . . . . . . 94
COV Subscription in a UNC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
COV Subscription in an ENC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Using AdminTool Object to Change useCOV Value . . . . . . . . . . . . . 98
Preparation for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Performing a Search and Replace . . . . . . . . . . . . . . . . . . . . . . . 100
Optimizing the covIncrement Value . . . . . . . . . . . . . . . . . . . . . . . . 101
COV Subscription Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
covIncrement Value too Small . . . . . . . . . . . . . . . . . . . . . . . . . . 101
covIncrement Value too Large . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Choose the Right covIncrement Value . . . . . . . . . . . . . . . . . . . . 102
The Type of Point Affects COV Efficiency . . . . . . . . . . . . . . . . . . . 103
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Setting Up a Remote I/O Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Installing Remote I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Configuring Remote I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . 105
The Remote I/O Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Understanding the Transmit and Receive Data LEDs on Remote I/O
Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
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Remote I/O Best Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EOL Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fallback Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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viii MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
Preface
Purpose of this
Manual
This TAC I/A Series MicroNet™ BACnet™ Wiring, Networking, and Best
Practices Guide is a reference for creating a network of TAC I/A Series
MicroNet BACnet controllers. This guide provides the following discussions
and instructions for the TAC I/A Series MicroNet BACnet series:
• Best practices related to the configuration and maintenance of a TAC I/A
Series MicroNet BACnet system
• TAC I/A Series MicroNet BACnet Controllers and Remote I/O Modules,
and their features
•
•
•
•
•
•
•
Controller and module wiring terminals and wiring recommendations
Controller and module input and output specifications
TAC I/A Series MicroNet Digital Wall Sensors and their features
Diagnostic functions of the TAC I/A Series MicroNet Digital Wall Sensors
BACnet overview
TAC I/A Series MicroNet BACnet system architecture overview
MS/TP and Remote I/O Network configuration, including physical and
logical restrictions
• How to network into an IP over an Ethernet backbone
Other literature related to the implementation of a TAC I/A Series MicroNet
BACnet system are referenced throughout this guide and are listed in
"Applicable Documentation,” on page x.
It is assumed that readers of this manual already understand basic HVAC
concepts. An understanding of BACnet networking and communications, as
well as a general understanding of Ethernet networks, is also helpful. This
manual is written for:
• Application engineers.
• Users who change hardware or control logic.
• Schneider Electric technicians and field engineers.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
ix
Applicable Documentation
F-Number
Description
Audience
Purpose
F-27254
TAC I/A Series WorkPlace Tech
Tool Engineering Guide.
– Application Engineers
– Service Personnel
Provides a programming reference for
MicroNet controllers. Gives detailed
descriptions for each of the Control Objects
used with MicroNet controllers.
F-27255
TAC I/A Series WorkPlace Tech
Tool User’s Guide
–
–
–
–
Application Engineers
Installers
Start-up Technicians
Service Personnel
Provides step-by-step instructions for using
the WorkPlace Tech Tool, version 4.0.
F-27356
TAC I/A Series WorkPlace Tech
Tool BACnet Engineering Guide
Supplement
– Application Engineers
– Service Personnel
Provides supplemental information for
programming MicroNet BACnet controllers.
Gives detailed descriptions for each of the
unique BACnet Control Objects used with
these controllers.
F-27419
– Application Engineers
TAC I/A Series MicroNet BACnet – Installers
Smoke Control Systems Manual – Start-up Technicians
– Service Personnel
Provides information for creating smoke
control systems that meet a UL 864
UUKL/UUKL7 project specification, using
MicroNet BACnet controllers.
F-27358
TAC I/A Series MicroNet BACnet
WorkPlace Commissioning Tool
and Flow Balance Tool User’s
Guide
Provides step-by-step instructions for using
the WorkPlace Commissioning Tool and
Flow Balance Tool.
F-27365
TAC I/A Series MicroNet BACnet
MNB-70, MNB-300, MNB-V1,
– Application Engineers
and MNB-V2 Controllers BACnet
PIC Statement
Provides BACnet compliance information
on MicroNet BACnet MNB-70, MNB-300,
MNB-V1, and MNB-V2 controllers.
F-27461
TAC I/A Series MicroNet BACnet
MNB-1000 Controller BACnet
– Application Engineers
PIC Statement
Provides BACnet compliance information
on the MicroNet BACnet MNB-1000
controller.
F-27462
TAC I/A Series UNC-520
Universal Network Controller
BACnet PIC Statement
– Application Engineers
Provides BACnet compliance information
on the UNC-520 controller.
F-27463
TAC I/A Series ENC-520
Enterprise Network Controller
BACnet PIC Statement
– Application Engineers
Provides BACnet compliance information
on the ENC-520 controller.
F-27485
TAC I/A Series ENS-1 Enterprise
Network Server BACnet PIC
– Application Engineers
Statement
Provides BACnet compliance information
on the ENS-1 enterprise network server.
F-27456
– Application Engineers
TAC I/A Series MicroNet BACnet
– Installers
MNB-70 Zone Controller
– Service Personnel
Installation Instructions
– Start-up Technicians
Provides step-by-step mounting and
installation instructions for the MicroNet
MNB-70 Controller.
F-27345
– Application Engineers
TAC I/A Series MicroNet BACnet
– Installers
MNB-300 Unitary Controller
– Service Personnel
Installation Instructions
– Start-up Technicians
Provides step-by-step mounting and
installation instructions for the MicroNet
MNB-300 Controller.
–
–
–
–
Application Engineers
Installers
Start-up Technicians
Service Personnel
x MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
Preface
F-Number
Description
Audience
F-27346
TAC I/A Series MicroNet BACnet
MNB-V1, MNB-V2 VAV
Controllers Installation
Instructions
Application Engineers
Installers
Service Personnel
Start-up Technicians
Provides step-by-step mounting and
installation instructions for the MicroNet
MNB-V1 and MNB-V2 Controllers.
F-27347
– Application Engineers
TAC I/A Series MicroNet BACnet
– Installers
MNB-1000 Plant Controller
– Service Personnel
Installation Instructions
– Start-up Technicians
Provides step-by-step mounting and
installation instructions for the MicroNet
MNB-1000 Controller.
F-27486
– Application Engineers
TAC I/A Series MicroNet BACnet
– Installers
MNB-1000-15 Remote I/O
– Service Personnel
Module Installation Instructions
– Start-up Technicians
Provides step-by-step mounting and
installation instructions for the MicroNet
MNB-1000-15 Remote I/O Module.
F-26277
TAC I/A Series MicroNet
MN-SX Series Sensors
General Instructions
Related
Documentation
Applies To
–
–
–
–
Purpose
–
–
–
–
Application Engineers
Installers
Service Personnel
Start-up Technicians
Provides step-by-step installation and
checkout procedures for TAC I/A Series
TAC I/A Series MicroNet MN-SX Series
Sensors. Also contains instructions for
sensor operation.
For more information, consult the following documentation:
Description
Source
Niagara Release 2.3.4 Installation and Upgrade
Instructions
UNC and ENC Network
Controllers
Niagara System and Power Monitoring, Engineering
• TAC I/A Series Enterprise Server
Notes
CD
Niagara Networking & Connectivity Guide
• Tech Zone at The Source
(http://source.tac.com/)
Niagara Standard Programming Reference Manual,
Release 2.3.4
BACnet Integration Reference
NiagaraAX BACnet Guide
NiagaraAX Networking and IT Guide
BACnet Networks
F-27360-11
ANSI/ASHRAE Standard 135-2001
BACnet—A Data Communication Protocol for
Building Automation and Control Networks.
• TAC I/A Series Enterprise Network
Server CD
• ANSI/ASHRAE
MicroNet BACnet Wiring, Networking, and Best Practices Guide
xi
Conventions Used
in this Manual
The following conventions apply to this printed manual:
• Menu commands appear in bold.
Example — On the Special menu, point to Security, then click Log On.
• Italics is used for emphasis in a statement, such as:
If maximum closed switch voltage is not more than 1.0 V and minimum
open switch voltage is at least 4.5 V, then solid state switches may be
used for a UI or a DI.
It is also used when referring to a document, such as:
Refer to the WorkPlace Tech Tool BACnet Engineering Guide Supplement, F-27356.
Acrobat (PDF) Conventions
If you are reading this manual online in Adobe® Acrobat® (.PDF file format),
numerous hypertext links exist, both in normal black text and in blue text.
• Hypertext links in this document include all entries in the Table of
Contents, as well as cross-references within the body text. For ease of
recognition, cross-reference links within the body text appear in blue
type, for example Manual Summary. A link is indicated whenever the
mouse pointer changes to a hand with a pointing finger.
• When viewing this guide with Adobe Acrobat, you can display various
“bookmark” links on the left side of your screen by choosing “Bookmarks
and Page” from the “View” menu. As with the links described above,
these “bookmark” links will also cause the mouse pointer to change to a
hand with a pointing finger.
Abbreviations and Terms Used in this Manual
Refer to Glossary for definitions, abbreviations, and acronyms that may be
used in this document:
Manual Summary
The MicroNet BACnet Wiring, Networking, and Best Practices Guide
contains three chapters.
Chapter 1, I/A Series BACnet Hardware, provides a brief overview of the
various I/A Series® MicroNet BACnet controllers, remote I/O modules, and
sensors.
Chapter 2, Networking Practices, provides an overview of the BACnet
protocol and, more specifically, its implementation in the TAC I/A Series
MicroNet BACnet system. This chapter then explains how TAC I/A Series
MicroNet BACnet controllers and sensors are configured for an MS/TP
network. It also explains how remote I/O networks are constructed by
connecting one to eight remote I/O modules to an MNB-1000 controller.
Chapter 3, Checkout and Troubleshooting, provides steps for determining
the proper operation of the TAC I/A Series MicroNet BACnet system and
suggests corrective actions for any discovered faults.
Appendix A, BACnet Best Practices, provides best practices information
for creating and maintaining a network of TAC I/A Series MicroNet BACnet
controllers, remote I/O modules, and sensors, and provides additional detail
for information contained elsewhere in this document.
xii MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
Chapter 1
I/A Series BACnet Hardware
This chapter provides a brief overview of the various I/A Series MicroNet
BACnet controllers and sensors, including:
•
•
•
•
•
•
•
•
Common Controller Features
BACnet Compliance
MNB-300 Unitary Controller
MNB-V1, MNB-V2 VAV Controllers
MNB-70 Zone Controllers
MNB-1000 Plant Controller
MNB-1000-15 Remote I/O Module
MicroNet Digital Wall Sensors (MN-Sx Series)
MicroNet BACnet hardware products include controllers and compatible
sensors.
• MicroNet BACnet controllers provide direct-digital control for packaged
rooftop, heat pump, fan coil, unit ventilator, and VAV, as well as complex
mechanical equipment such as central station air handlers, VAV air
handlers, and cooling towers. Five basic controller platforms are
available, each with a number of I/O points and support for a digital room
temperature or humidity sensor (MicroNet sensor).
• MicroNet sensors are digital wall temperature and humidity sensors
designed specifically for use with MicroNet controllers. 12 different
models offer varying levels of sensor push-buttons and LCD screens.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
1
Chapter 1
MicroNet BACnet Controllers
There are five hardware platforms for MicroNet BACnet controllers: the
MNB-70, the MNB-300, the MNB-V1, the MNB-V2, and the MNB-1000. In
addition, the MicroNet BACnet family includes the MNB-1000-15 remote I/O
module. Each of these platforms is described in the following sections.
Common Controller
Features
While all controller platforms differ by their physical characteristics and
numbers and types of I/O points, all controller platforms provide the following
common features:
Note: See"MNB-1000-15 Remote I/O Module" on page 13 for features of
the remote I/O module.
• 24 Vac powered.
• Capability to function in standalone mode or as part of an I/A Series
building automation network.
• Support for a digital MicroNet sensor via a Sensor Link (S-Link) bus.
• Sequence of operation and BACnet image are fully programmable using
WorkPlace Tech Tool (WP Tech) 5.0 or greater.
• Extensive BACnet object and services support.
• DIP switch for setting the physical address.
• LED indication of MS/TP communication link and activity, and controller
status.
• Isolated EIA-485 (formerly RS-485) transceiver for MS/TP
communications.
• Firmware upgradeable over the network or directly to the controller.
BACnet
Compliance
Each MicroNet BACnet controller conforms to the requirements of a BACnet
Application Specific Device (B-ASD). For a list of objects supported by these
controllers, and the services provided, refer to the BACnet PIC Statements,
available on the BACnet Testing Laboratories website
(http://www.bacnetinternational.net/btl/).
2 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
MNB-300 Unitary
Controller
The I/A Series MicroNet BACnet Unitary Controller, MNB-300, is an
interoperable controller with native BACnet MS/TP communications support.
The controller features Sensor Link (S-Link) support, LED status and output
indication, screw terminal blocks, as well as a panel-mount sub-base with
removable electronics module. The MNB-300 also includes one end-of-line
(EOL) termination and two bias resistors, both of which are
jumper-selectable.
When programmed using WP Tech, the MNB-300 provides a wide range of
control strategies for packaged rooftop, heat pump, fan coil, unit ventilator,
and similar applications.
Unique Features
In addition to common MicroNet BACnet controller features ("Common
Controller Features" on page 2), the MNB-300 offers the following:
•
•
•
•
•
Removable electronics module that mates with panel-mounted subbase.
Optional NEMA 1 enclosure.
IAM button for BACnet “I am” message broadcast.
Integral MS/TP jack for direct connection of a PC with the WP Tech.
Removable terminals for power and communications, to facilitate
commissioning.
• LED indication of UO and TO state.
Memory Available
Table–1.1 MNB-300 Available Memory.
Model
Number
MNB-300
Flash
SRAM
SDRAM
EEPROM
FRAM
256 KB
8 KB
n/a
4 KB
8 KB
Physical I/O Points
Table–1.2 MNB-300 Inputs and Outputs.
Model
Number
MNB-300
UI
6
Inputs and Outputs
UO
DO (Triac)
3
6
Refer to "Input and Output Specifications" on page 15 for a detailed
discussion of each input or output type.
Time Clock
The MNB-300 controller uses a software clock. This software clock defaults to
a predefined Date/Time following a reset.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
3
Chapter 1
Wiring Terminals
Refer to Figure-1.1 for the power and network communications wiring connections
available on the MNB-300 controller.
2
MNB-300
Unitary Controller
UI1
Universal Inputs
0 to 5 Vdc 4
5
0 to 20 mA
6
10K Thermistor
1K Balco
1K Platinum
1K Resistive
10K Resistive
Digital (dry switched
contact)
7
8
24G COM
COM
GND
UI2
AC Power
20.4 to 30 Vac
50/60 Hz
Class 2 (EN 60742)
16 VA per controller
TO1 (DO1)
Internal
Triac
Switches
(Isolated)
UI3
COM
2
C1
TO2 (DO2)
UI4
Standard Pulse 10
Fast Pulse (UI1) 12
3
24H
C2
UI5
TO3 (DO3)
Digital Outputs
(Triac)
12 VA at 24 Vac,
50/60 Hz. Each Triac
output individually
isolated from AC
input and other I/O.
Class 2
COM
C3
UI6
TO4 (DO4)
Universal Outputs
0 to 20 mA into an
80 to 550 ohm load
UO1
C4
Connectors (2)
COM
UO2
TO5 (DO5)
UO LEDs (3)
9
S-LK
Supports one
TAC I/A Series
MN-Sxxx Sensor
C5
XMT
UO3
Disable
COM
IAM
S-LK
13
Do not exceed two AWG #24
(0.205 mm2) wires per MS/TP
wiring terminal.
2
Power and I/O point wiring
terminals accept up to two AWG
#14 (2.08 mm2) or smaller wires.
Enable
MS+
EOL
MS-
1
SLD
3
LSB
MSB
BACnet Network
MS/TP Communications
1
TO6 (DO6)
6
C6
Physical
Address
2
EN DIS
MS/TP Jack
STATUS
RCV
MS BIAS
TO (DO) LEDs (6)
11
An 11 kilohm shunt resistor kit, part
number AD-8969-206, is required for a
10 kilohm Thermistor Sensor (non-850
series) universal inputs.
7
To detect a closed switch, resistance must
be less than 300 ohm.
3
Power and MS/TP connectors
have removable screw terminals.
8
To detect an open switch, resistance must
be greater than 2.5 kilohm.
4
Input signals of 1 to 11 Vdc must
be converted to 0.45 to 5 Vdc with
a voltage divider, part number
AD-8961-220.
9
External load is not required to illuminate
UO LEDs.
5
In applications requiring universal
inputs with ranges of 0 to 20 mA,
a 250 ohm shunt resistor kit, part
number AD-8969-202, is needed.
10
Minimum rate of 1 pulse per 4 minutes.
Maximum rate of 1 pulse per second.
11
MS/TP network bias resistors are shipped
in the disabled setting, and are located
under the controller’s cover.
Note: Components are
shown in their
approximate locations.
12 Minimum rate of 1 pulse per 4 minutes.
Maximum rate of 10 pulses per second.
13 When making an MS/TP cable, use a
1.3 x 3.5 mm Vdc power plug with strain
relief (Vimex part number
SCP-2009A-T, TAC part number
E24-1442, or equivalent). The cable
should be no longer than 6 ft. Connect
MS+ to the center contact and MS– to
the outside contact:
_
Note: The MS/TP cable
described above is
available from
Schneider-Electric as
MNB-CT-CBL. Contact
Schneider-Electric for
more information.
+
Figure–1.1 MNB-300 Terminal Connections.
4 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
MNB-V1, MNB-V2
VAV Controllers
SW
24
SW H1
24
SW H2
24
2 4 H H3
24G
(C
GN OM)
D
ST
MSATUS
MSTP R
TP CV
XM
T
The I/A Series MicroNet BACnet VAV (Variable Air Volume) Controllers,
MNB-V1 and MNB-V2, are interoperable controllers with native BACnet
MS/TP communications support. Both models incorporate: an integral
actuator with manual override; an integral, patented, pressure transducer;
three universal inputs; Sensor Link (S-Link) support; LED status indication;
and over-the-shaft damper mounting. The MNB-V1 controller is designed
specifically for cooling applications, while the MNB-V2 controller adds digital
and universal outputs that make it suitable for additional VAV applications.
When programmed using WP Tech, these controllers provide a wide range
of control strategies for pressure-dependent and pressure-independent
terminal boxes, with or without reheat capabilities.
UO
1
CO
M
UI
1
CO
M
UI
2
S-L UI
K/C 3
MS OM
T
MS P +
TP
SH LD
Unique Features
In addition to common MicroNet BACnet controller features ("Common
Controller Features" on page 2), the MNB-V1 and MNB-V2 offer the
following:
• Air balancing performed using WorkPlace Flow Balance Tool (WPFBT).
• Integrated packaging with actuator, pressure transducer, and controller.
• Integral actuator features manual override and travel limit stops for easy
set up and adjustment.
• Enclosure approved for use in air plenums.
• Damper position feedback to the BACnet Building Automation System
(BAS) via integral hall effect sensor.
• Stable flow control down to 0.004 in. W.C. (0.996 Pa) differential
pressure.
Memory Available
Table–1.3 MNB-Vx Available Memory.
Model
Number
MNB-V1
MNB-V2
Flash
SRAM
SDRAM
EEPROM
FRAM
256 KB
8 KB
n/a
4 KB
n/a
Physical I/O Points
Table–1.4 MNB-Vx Inputs and Outputs.
Model
Number
MNB-V1
MNB-V2
UI
3
3
Inputs and Outputs
UO
DO (Triac)
0
0
1
3
Refer to the "Input and Output Specifications" on page 15 for a detailed
discussion of each input or output type.
Time Clock
The MNB-V1 and MNB-V2 controllers use a software clock. This software clock
defaults to a predefined Date/Time following a reset.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
5
Chapter 1
Wiring Terminals
Refer to Figure-1.2 for the power and network communications wiring connections
available on the MNB-V1 and MNB-V2 controllers.
MNB-V1 / -V2
Controllers
Internal Triac
Switches (3)
1
UO1*
Digital Outputs
Total 24 VA (DO1+DO2),
12 VA (DO3) at 24 Vac,
50/60 Hz, Class 2.
Pilot Duty
COM*
1
UI1
SW24H1* (DO1)
COM
SW24H2* (DO2)
UI2
SW24H3* (DO3)
UI3
24H
Universal Output
0 to 20mA into an
80 to 550 ohm
load
Universal Inputs
0 to 5 Vdc 2
3
0 to 20 mA
10K Thermistor
4
1K Balco
1K Platinum
1K Resistive
10K Resistive
Digital (dry switched
contact) 5
6
Standard Pulse
S-LK/COM
7
24G (COM)
AC Power
20.4 to 30 Vac,
50/60 Hz
Class 2 (EN 60742)
15 VA per controller
plus DO load
S-LK
GND
LSB
MSTP +
STATUS
Physical
MSTP RCV
MS/TP Jack
MSTP XMT
S-LK
Supports one I/A
Series MN-Sxxx
Sensor
MSTP –
8
MSB
SHLD
Address
Note: Asterisks (*) indicate terminals
that apply to the MNB-V2
controller but not to the MNB-V1.
Note: Components are shown in
their approximate locations.
BACnet Network
Communications
Fixed screw terminals that accept a single AWG #14
(2.08 mm2) wire or up to two AWG #18 (0.823 mm2) or
smaller wires. Do not exceed two AWG #24 (0.205 mm2)
wires per MS/TP wiring terminal.
6
To detect an open switch, minimum resistance must be
greater than 2.5 kilohm.
7
Minimum rate of 1 pulse per 4 minutes. Maximum rate of
1 pulse per second.
2
Input signals of 1 to 11 Vdc must be converted to 0.45 to
5 Vdc with a voltage divider, part number AD-8961-220.
8
3
In applications requiring universal inputs with ranges of
0 to 20 mA, a 250 ohm shunt resistor kit,
AD-8969-202, is needed.
4
An 11 kilohm shunt resistor kit, AD-8969-206, is
required for a 10 kilohm Thermistor Sensor (non-850
series) universal inputs.
When making an MS/TP cable, use a 1.3 x 3.5 mm Vdc
power plug with strain relief (Vimex part number
SCP-2009A-T, Schneider-Electric part number E24-1442,
or equivalent). The cable should be no longer than 6 ft.
Connect MS+ to the center contact and MS– to the
outside contact:
1
5
To detect a closed switch, maximum resistance must
be less than 300 ohm.
Note: The MS/TP cable described above
is available from Schneider-Electric as
MNB-CT-CBL. Contact
Schneider-Electric for more information.
_
+
Figure–1.2 MNB-Vx Terminal Connections.
6 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
MNB-70 Zone
Controllers
SW
24
SW H1
24
SW H2
24
24H H3
24G
(C
GN OM)
D
ST
MSATUS
T
MS P R
TP CV
XM
T
The I/A Series MicroNet BACnet Zone Controller, MNB-70, is an
interoperable controller with native BACnet MS/TP communications support.
The controller features: three universal inputs; one universal output; three
digital (Triac) outputs; Sensor Link (S-Link) support; LED status indication;
and screw terminal blocks.
When programmed using WP Tech, the MNB-70 provides a wide range of
control strategies for heat pump, fan coil, unit ventilator, mixing boxes, and
similar applications.
Unique Features
UO
1
COAO
M
UI
1
CO
M
UI
2
S-L UI
K/C 3
MS OM
T
MS P +
TP
SH LD
In addition to common MicroNet BACnet controller features ("Common
Controller Features" on page 2), the MNB-70 offers the following:
•
•
•
•
I-Am button for BACnet “I-am” message broadcast.
Integral MS/TP jack for direct connection of a PC with the WP Tech.
Small footprint.
Enclosure approved for use in air plenums.
Memory Available
Table–1.5 MNB-70 Available Memory.
Model
Number
MNB-70
Flash
SRAM
SDRAM
EEPROM
FRAM
256 KB
8 KB
n/a
4 KB
n/a
Physical I/O Points
Table–1.6 MNB-70 Inputs and Outputs.
Model
Number
MNB-70
UI
3
Inputs and Outputs
UO
DO (Triac)
1
3
Refer to the "Input and Output Specifications" on page 15 for a detailed
discussion of each input or output type.
Time Clock
The MNB-70 controller uses a software clock. This software clock defaults to a
predefined Date/Time following a reset.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
7
Chapter 1
Wiring Terminals
Refer to Figure-1.3 for the power and network communications wiring connections
available on the MNB-70 controller.
MNB-70
Controller
Internal Triac
Switches (3)
1
UO1
Digital Outputs
Total 24 VA (DO1+DO2),
12 VA (DO3) at 24 Vac,
50/60 Hz, Class 2.
Pilot Duty
COM
1
UI1
SW24H1 (DO1)
COM
SW24H2 (DO2)
UI2
SW24H3 (DO3)
UI3
24H
Universal Output
0 to 20mA into an
80 to 550 ohm
load
Universal Inputs
0 to 5 Vdc 2
3
0 to 20 mA
10K Thermistor
4
1K Balco
1K Platinum
1K Resistive
10K Resistive
Digital (dry switched
contact) 5
6
Standard Pulse
S-LK/COM
7
24G (COM)
AC Power
20.4 to 30 Vac,
50/60 Hz
Class 2 (EN 60742)
15 VA per controller
plus DO load
S-LK
GND
LSB
MSTP +
STATUS
Physical
Address
MSTP RCV
MSTP XMT
S-LK
Supports one I/A
Series MN-Sxxx
Sensor
MSTP –
MS/TP Jack
8
MSB
SHLD
IAM
BACnet Network
Communications
Note: Components are shown in
their approximate locations.
Fixed screw terminals that accept a single AWG #14
(2.08 mm2) wire or up to two AWG #18 (0.823 mm2) or
smaller wires. Do not exceed two AWG #24 (0.205 mm2)
wires per MS/TP wiring terminal.
6
To detect an open switch, minimum resistance must be
greater than 2.5 kilohm.
7
Minimum rate of 1 pulse per 4 minutes. Maximum rate of
1 pulse per second.
2
Input signals of 1 to 11 Vdc must be converted to 0.45 to
5 Vdc with a voltage divider, part number AD-8961-220.
8
3
In applications requiring universal inputs with ranges of
0 to 20 mA, a 250 ohm shunt resistor kit,
AD-8969-202, is needed.
4
An 11 kilohm shunt resistor kit, AD-8969-206, is
required for a 10 kilohm Thermistor Sensor (non-850
series) universal inputs.
When making an MS/TP cable, use a 1.3 x 3.5 mm Vdc
power plug with strain relief (Vimex part number
SCP-2009A-T, Schneider-Electric part number E24-1442,
or equivalent). The cable should be no longer than 6 ft.
Connect MS+ to the center contact and MS– to the
outside contact:
1
5
To detect a closed switch, maximum resistance must
be less than 300 ohm.
Note: The MS/TP cable described above
is available from Schneider-Electric as
MNB-CT-CBL. Contact
Schneider-Electric for more information.
_
+
Figure–1.3 MNB-70 Terminal Connections.
8 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
MNB-1000
Plant Controller
The I/A Series MicroNet BACnet Plant Controller, MNB-1000, is an
interoperable controller with native BACnet MS/TP communications support.
The controller features Sensor Link (S-Link) support, LED status and output
indication, two Ethernet ports, and screw terminal blocks.
The MNB-1000’s sequence of operation and BACnet image are fully
programmable using WP Tech, and can be applied to a wide range of
mechanical equipment. Typical applications include central station air
handlers, VAV air handlers, and cooling towers.
Unique Features
In addition to common MicroNet BACnet controller features ("Common
Controller Features" on page 2), the MNB-1000 offers the following:
•
•
•
•
Optional NEMA 1 enclosure.
IAM button for BACnet “I am” message broadcast.
Integral MS/TP jack for direct connection of a PC with the WP Tech.
LED indication of Ethernet communication link and activity, DO state,
UO state, and remote I/O communications.
• Application-programmable LED provides on/off indication of a
user-defined application parameter.
•
•
•
•
•
BACnet router functionality.
Support for remote I/O modules.
Ethernet port bridging.
20 Vdc output
72 hour, battery-backed real time clock.
Memory Available
Table–1.7 MNB-1000 Available Memory.
Component
µC
Motherboard
Flash
128 KB
n/a
SRAM
4 KB
256 KB
SDRAM
n/a
n/a
EEPROM
4 KB
128 KB
FRAM
n/a
n/a
Engine (Core)
Engine (Boot)
32 or 16 MBa
2 MB
n/a
n/a
64 MB
n/a
1 Kb
n/a
n/a
n/a
a. MNB-1000s with a date code prior to 0726 have 32 MB of core memory. Beginning with
date code 0726, core memory was changed to 16 MB. However, because the MNB-1000
has always used only the first 16 MB of memory, this change has no impact on the
controller’s operation, the size of the application allowed, or the controller’s application
compatibility.
Physical I/O Points
Table–1.8 MNB-1000 Inputs and Outputs.
Model
MNB-1000
UI
12
Inputs and Outputs
DI
UO
4
8
DO (Triac)
8
Refer to the "Input and Output Specifications" on page 15 for a detailed
discussion of each input or output type.
F-27360-11
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9
Chapter 1
Note: The onboard I/O points of the MNB-1000 can be greatly expanded
with the addition of one to eight MNB-1000-15 remote I/O modules, each of
which adds 15 I/O points. Refer to "MNB-1000-15 Remote I/O Module" on
page 13.
Time Clock
The MNB-1000 features an onboard, real-time clock. A lithium battery
provides backup power for up to 72 hours in the event of a primary power
interruption. The real-time clock acts as a Date/Time server using native
BACnet services. In the absence of another Date/Time server on the
network, the MNB-1000 can provide this functionality to other nodes on the
BACnet internetwork.
Battery Replacement
If the real-time clock’s battery becomes depleted, replace it with lithium
battery, part number E17-137, according to the instructions in Figure-1.4.
For additional disassembly and reassembly instructions, refer to MicroNet
BACnet MNB-1000 Plant Controller Installation Instructions, F-27347
Caution: Follow static discharge precautions when handling the MNB-1000
and its component parts.
Note: Whenever the battery is removed from the MNB-1000, the clock
setting and volatile data will be lost. Reprogram the MNB-1000 as needed
after installing the replacement battery.
10 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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I/A Series BACnet Hardware
1
If the controller is mounted inside an
enclosure, open the enclosure cover.
9
Restore power to the controller.
2
Remove power from the
controller.
10 If applicable, close the enclosure
cover.
3
Referring to MicroNet BACnet
MNB-1000 Controller Installation
Instructions, F-27347, remove
the controller’s main assembly
from the base plate.
4
Remove two screws, and then
separate the printed circuit
board from the cover.
5
Locate the battery on the printed
circuit board.
6
Remove the depleted battery,
and then install a new lithium
battery, part number E17-137.
Make sure that the positive (+)
side faces upward.
7
Reassemble the printed
circuit board to the cover,
and secure with the two
screws removed in step 4.
8
Referring to F-27347,
reassemble the
controller’s main
assembly to the base
plate.
Printed Circuit
Board
Cover
Screw
(1 of 2)
Base Plate
Lithium Battery
E17-137
Printed Circuit Board
Figure–1.4 MNB-1000 Real-time Clock Battery Replacement.
F-27360-11
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11
Chapter 1
Wiring Terminals
Refer to Figure-1.5 for the wiring connections available on the MNB-1000 controller.
20 Vdc Output
20 Vdc ±10% at
100 mA
UI1
UI2
UI3
GND
1
TO1 (DO1)
C1
COM
0 to 5 Vdc 4
0 to 20 mA
5
10K Thermistor
6
1K Balco
1K Platinum
1K Resistive
10K Resistive
Digital (dry switched
contact)
7
9
TO2 (DO2)
Note: Components are
shown in their
approximate
locations.
UI4
UI5
COM
C2
TO (DO)
LEDs (8)
TO4 (DO4)
UI7
C4
COM
TO5 (DO5)
UI8
C5
UI9
1
TO6 (DO6)
COM
C6
TO7 (DO7)
C7
COM
C8
DI1
ACT
DI3
COM
LD
XMT
IO+
SLD
8
1
MS-
3
I/O point wiring terminals
accept a single AWG #14
(2.08 mm2) or up to two
AWG #18 (0.823 mm2) or
smaller wires. Do not
exceed two AWG #24
(0.205 mm2) wires per
MS/TP or Remote I/O
wiring terminal.
UO4
UO5
IO
MSTP
AUX
COM
13
To detect a closed
switch, maximum
resistance must be
less than 300 ohm.
8
Remote I/O network
bias resistor is built-in.
UO7
UO8
ETHERNET
I AM
7
UO6
COM
9
LSB
Physical
Address
To detect an open switch,
minimum resistance must
be equal to or greater than
2.5 kilohm.
11
External load is required to
illuminate UO LEDs.
MSB
Power wiring terminals accept up to two AWG #14
(2.08 mm2) or smaller wires.
3
Power, MS/TP, and Remote I/O connectors have
removable screw terminals.
4
Input signals of 1 to 11 Vdc must be converted to 0.45 to
5 Vdc with a voltage divider, part number AD-8961-220.
5
In applications requiring universal inputs with ranges of 0 to
20 mA, a 250 ohm shunt resistor kit, AD8969-202, is
needed.
To detect an open switch,
minimum resistance must be
greater than 2.5 kilohm.
10
MS/TP Jack
2
6
COM
IO EOL
MS BIAS
MS EOL
MS BIAS
SLD
1
STATUS
Disable Enable
MS+
BACnet Network
Communications
COM
UO3
S-LK
IO-
Universal Outputs
0 to 20 mA into an
80 to 550 ohm
load.
UO1
UO2
COM
3
11
RCV
S-LK
Supports one I/A
Series MN-Sxxx
Sensor
UO LEDs (8)
LNK
DI4
1
1 PORT
0 PORT
DI2
Local Display
(for future use)
1
Digital Outputs
12 VA at 24 Vac,
50/60 Hz each Triac
output individually
isolated from AC
input and other I/O.
TO8 (DO8)
UI12
COM
ADI or
Remote I/O
AC Power
20.4 to 30 Vac
50/60 Hz
Class 2 (EN 60742)
50 VA per controller
Isolated from I/O
C3
UI6
UI11
10
3
TO3 (DO3)
UI10
Digital Inputs
Dry Switched
7
Contact
Fast Pulse 12
2
24G COM
Internal Triac
Switches (8)
(Isolated)
COM
Universal Inputs
24H
MNB-1000
Plant Controller
20V
12
Minimum rate of 1 pulse per 4 minutes. Maximum rate of 10 pulses
per second. With digital inputs only.
13
When making an MS/TP cable, use a 1.3 x 3.5 mm Vdc power
plug with strain relief (Vimex part number SCP-2009A-T,
Schneider-Electric part number E24-1442, or equivalent). The
cable should be no longer than 6 ft. Connect MS+ to the center
contact and MS– to the outside contact:
–
+
Note: The MS/TP cable described above
is available from Schneider-Electric as
MNB-CT-CBL. Contact
Schneider-Electric for more information.
An 11 kilohm shunt resistor kit, AD-8969-206, is required
for a 10 kilohm thermistor Sensor (non-850 series)
universal inputs.
Figure–1.5 MNB-1000 Terminal Connections.
12 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
MNB-1000-15
Remote I/O Module
The I/A Series MicroNet BACnet Remote I/O Module, MNB-1000-15, is
designed to be connected to an MNB-1000 Plant Controller, so as to expand
the controller’s I/O count. When programmed using WP Tech, each module
increases the count by 15 inputs and outputs. Up to eight modules can be
connected to a given MNB-1000, for a potential increase of 120 I/O points,
total. In this way, the controller’s existing 32 onboard I/O can be expanded to
47 I/O points (with one module), up to a maximum total of 152 I/O points
(with eight modules).
Features
The MNB-1000-15 offers the following:
• 24 Vac powered.
• DIP switch for setting the physical address on the remote I/O network.
• Isolated EIA-485 (formerly RS-485) transceiver for remote I/O
communications.
• Removable electronics module that mates with panel-mounted subbase.
• Optional NEMA 1 enclosure.
• Removable terminals for power and communications, to facilitate
commissioning.
• LED indication of compatibility, UO and TO state, and communication
state (with the MNB-1000).
• Firmware upgradeable over the network.
• Fallback function, in case of loss of communication with MNB-1000.
Note: The MNB-1000-15 does not support the S-Link bus.
Memory Available
Table–1.9 MNB-1000-15 Available Memory.
Model
Number
MNB-1000-15
Flash
SRAM
SDRAM
EEPROM
FRAM
256 KB
8 KB
n/a
4 KB
8 KB
Physical I/O Points
Table–1.10 MNB-1000-15 Inputs and Outputs.
Model
Number
MNB-1000-15
UI
6
Inputs and Outputs
UO
DO (Triac)
3
6
Refer to "Input and Output Specifications" on page 15 for a detailed
discussion of each input or output type.
Fallback Function
The MNB-1000-15 module’s outputs are driven directly by the MNB-1000
Plant Controller, in which the application resides. If communications
between the module and the MNB-1000 is lost, the module’s outputs are set
to fallback values that were previously sent to the module during normal
communications. Refer to "Fallback Function" on page 107 for more
information on this function.
F-27360-11
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13
Chapter 1
Wiring Terminals
Refer to Figure-1.6 for the power and network communications wiring
connections available on the MNB-1000-15 remote I/O module.
2
MNB-1000-15
Remote I/O Module
UI1
Universal Inputs
0 to 5 Vdc 4
5
0 to 20 mA
6
10K Thermistor
1K Balco
1K Platinum
1K Resistive
10K Resistive
Digital (dry switched
contact)
7
8
Standard Pulse
(UI1-UI6)
10
3
24H
24G COM
COM
GND
UI2
AC Power
20.4 to 30 Vac
50/60 Hz
Class 2 (EN 60742)
16 VA per module
TO1 (DO1)
Internal
Triac
Switches
(Isolated)
UI3
COM
2
C1
TO2 (DO2)
UI4
C2
UI5
TO3 (DO3)
Digital Outputs
(Triac)
12 VA at 24 Vac,
50/60 Hz. Each Triac
output individually
isolated from AC
input and other I/O.
Class 2
COM
C3
UI6
TO4 (DO4)
Universal Outputs
0 to 20 mA into an
80 to 550 ohm load
UO1
C4
Connectors (2)
COM
UO2
TO5 (DO5)
UO LEDs (3)
9
C5
XMT
UO3
Disable
COM
11
S-LK
11
Enable
IO+
EOL
IO-
1
SLD
3
Do not exceed two AWG #24
(0.205 mm2) wires per Remote I/O
wiring terminal.
2
Power and I/O point wiring
terminals accept up to two AWG
#14 (2.08 mm2) or smaller wires.
3
Power and remote I/O connectors
have removable screw terminals.
4
Input signals of 1 to 11 Vdc must
be converted to 0.45 to 5 Vdc with
a voltage divider, part number
AD-8961-220.
LSB
TO6 (DO6)
5
6
C6
Physical
Address
2
TO (DO) LEDs (6)
MSB
Remote I/O Network
Communications to
MNB-1000
1
STATUS
RCV
11
12
In applications requiring universal inputs
with ranges of 0 to 20 mA, a 250 ohm
shunt resistor kit, part number
AD-8969-202, is needed.
An 11 kilohm shunt resistor kit, part
number AD-8969-206, is required for a
10 kilohm Thermistor Sensor (non-850
series) universal inputs.
7
To detect a closed switch, resistance must
be less than 300 ohm.
8
To detect an open switch, resistance must
be greater than 2.5 kilohm.
9
Note: Components are shown
in their approximate
locations.
External load is not required to
illuminate UO LEDs.
10 Minimum rate of 1 pulse per 4 minutes.
Maximum rate of 1 pulse per second.
11 Items in gray, although present, are not
used in the MNB-1000-15.
12 Bias for the remote I/O network is
provided by the built-in bias resistor on
the MNB -1000 controller.
Figure–1.6 MNB-1000-15 Terminal Connections.
14 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
Input and Output
Specifications
All MicroNet BACnet controllers use input and output types as described in
this section.
Universal Inputs
The universal input characteristics are software-configured to respond to
one of the eight input types listed in Table–1.11.
Table–1.11 Universal Inputs.
Input
Characteristics
10 kilohm Thermistor Sensor operating range -40 to 250 °F (-40 to 121 °C),
with 11 kilohm Shunt requires Schneider Electric model TSMN-57011-850
Resistor
series, TS-5700-850 series, or equivalent.
-40 to 250 °F (-40 to 121 °C), Schneider Electric model
1 kilohm Balco
TSMN-81011, TS-8000 series, or equivalent.
-40 to 240 °F (-40 to 116 °C), Schneider Electric model
1 kilohm Platinum
TSMN-58011, TS-5800 series, or equivalent.
1 kilohm Resistive
0 to 1500 ohm.
10 kilohm Resistive
0 to 10.5 kilohm.
Analog Voltage
Range 0 to 5 Vdc
0 to 20 mA, requires external 250 ohm shunt resistor kit,
Analog Current
AD-8969-202.
Dry switched contact; detection of closed switch requires
Digital
less than 300 ohm resistance; detection of open switch
requires more than 2.5 kilohm.
See Figure-1.7 for examples of connections to universal inputs.
10 kilohm Thermistor
(with an 11 kilohm
Controller
shunt resistor)
Controller
Inputs
4 to 20 mA
Transmitter
+
_
UI1
COM
250 ohm
UI2
UI1
COM
1
UI2
Sensor Power
Source
0 to 5 Vdc
Transmitter
+
_
Controller
Inputs
UI1
COM
UI2
1
Resistor kit, AD-8969-202. Be
sure to install the resistor at the
controller, not at the 4 to 20 mA
device.
Sensor Power
Source
Figure–1.7 Universal Input Connections.
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Chapter 1
Universal Outputs
0 to 20 mA (output load from 80 to 550 ohm). See Figure-1.8 for examples of
connections to universal outputs.
Controller
Outputs
4 to 20 mA
Actuator
Controller Output
Configured as
0 to 20 mA
+
_
UO1
COM
UO2
Controller
Outputs
UO1
1
500 ohm
COM
UO2
0 to 10 Vdc
Actuator
+
_
2
Functional Devices
RIBU1C Relay 3
N/C
UO1
Wht/Blu
10-30 Vdc
COM
Wht/Yel
COM
COM
N/O
1
Output accuracy degrades as input
impedance decreases.
2
Resistor kit, AM-708. Be sure to
install the resistor at the 0 to 10 Vdc
device, not at the controller.
3
Can be purchased through PS3,
part number FUN-RIBU1-C.
Figure–1.8 Universal Output Connections.
Digital Inputs
Dry switched contact. Detection of a closed switch requires less than
300 ohm resistance. When connected to a controller’s digital inputs,
detection of an open switch requires more than 2.5 kilohm. When connected
to a controller’s universal inputs (used as digital inputs), detection of an open
switch requires more than 2.5 kilohm. See Figure-1.9 for examples of a
connection to digital inputs.
Connection to Digital Inputs
DI Input
On-Off Type Device
NC
Controller
Inputs
Connection to Universal Inputs
DI Input
On-Off Type Device
DI1
NC
DI2
NO
UI1
COM
COM
COM
Controller
Inputs
UI2
COM
NO
Figure–1.9 Fixed Digital Input Connections.
16 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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I/A Series BACnet Hardware
Digital Outputs, Triac
MNB-V2 and MNB-70
Table–1.12 lists specifications for the Triac outputs featured on the MNB-V2
and MNB-70 controllers.
Caution: The Triac (digital) outputs on MicroNet BACnet controllers are not
protected against short circuits. Take necessary precautions to protect these
outputs against short circuits.
Table–1.12 Digital Outputs, Triac, on MNB-V2 and MNB-70.
Characteristicsa
Input
Common Terminal
Rating (DO1+DO2)b
Rating (DO3)b
Default Output State
Internally sourced, high side switching. Triac outputs
share a common supply (24H) that is independently
switched to each output terminal, SW24H1, SW24H2, and
SW24H3 (DO1, DO2, and DO3).
24 VA total at 24 Vac, 50/60 Hz.
12 VA at 24 Vac, 50/60 Hz.
OFF (inactive).
a. As with all Triac devices, a high-impedance meter on the output without a load will show
24 Vac, due to low level leakage through the device.
b. As labeled on the controller, SW24H1=DO1, SW24H2=DO2, and SW24H3=DO3 (see
Figure-1.2).
See Figure-1.10 for an example of a connection to an MNB-V2 or MNB-70
controller’s Triac outputs.
Load1
Load2
SW24H1
(DO1)
SW24H2
(DO2)
Load3
SW24H3
(DO3)
MNB-V2
Controller
GND
24G
24H
24 Vac
Primary
Class 2
Transformer
Figure–1.10 MNB-V2 and MNB-70 Controller Triac Output Circuit Configuration.
F-27360-11
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Chapter 1
Note: With the MNB-V2 and MNB-70, AC voltage to Triacs is sourced from
the controller. This is different from the MNB-300 and MNB-1000 controllers,
and the MNB-1000-15 module, where AC voltage is sourced externally.
MNB-300, MNB-1000, and MNB-1000-15
Table–1.13 lists specifications for the Triac outputs featured on MNB-300
and MNB-1000 controllers, and on the MNB-1000-15 remote I/O module.
Caution: The Triac (digital) outputs on MicroNet BACnet controllers are not
protected against short circuits. Take necessary precautions to protect these
outputs against short circuits.
Table–1.13 Digital Outputs, Triac, on MNB-300, MNB-1000, and MNB-1000-15.
Characteristicsa
Input
Isolation
Common Terminal
Rating
Default Output State
Each output individually isolated from circuit common.
Each TO has its own common terminal. This is the voltage
switched to each TO output.
12 VA at 24 Vac, 50/60 Hz.
OFF (inactive).
a. As with all Triac devices, a high-impedance meter on the output without a load will show
24 Vac, due to low level leakage through the device.
See Figure-1.11 for an example of a connection to the Triac outputs on an
MNB-300, MNB-1000, or MNB-1000-15.
24 Vac
24 Vac
Load1
TO1 (DO1)
GND
Load2
C1
24G
TO2 (DO2)
24H
24 Vac
Loadx
C2
TOx (DOx)
Cx
Class 2
Transformer
24 Vac
Primary
Figure–1.11 MNB-300 Controller, MNB-1000 Controller, and MNB-1000-15 Remote
I/O Module Triac Output Circuit Configuration.
20 Vdc Output
20 Vdc ±10% at 100 mA for supplying power to an external device. See
Figure-1.12 for an example of a connection to a 20 Vdc output.
18 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
Auxiliary Device
Controller
+
20V
–
250 ohm
Humidity 4 to 20 mA
(example)
UI1
COM
1
1
Resistor kit, AD-8969-202,
4 to 20 mA only. Not
required for Vdc.
Figure–1.12 20 Vdc Output Connection.
Inputs from MN-Sx MicroNet Sensor
Table–1.14 lists specifications for the inputs from MicroNet Sensors. For an
example showing how a MicroNet Sensor may be wired to a MicroNet
BACnet controller, see Figure-1.13.
Table–1.14 Inputs from MN-Sx MicroNet Sensor.
Input
Space Temperature
Space Humidity
Local Setpoint
Override Pushbutton
Fan Operation and
Speed Mode
System Mode
Emergency Heat
F-27360-11
Characteristics
32 to 122 °F (0 to 50 °C).
5 to 95% RH, non-condensing.
Adjustable within limits set by application programming
tool.
For standalone occupancy control.
On/off, speed (low/medium/high), or auto.
Heat, cool, off, or auto.
Enable or disable.
MicroNet BACnet Wiring, Networking, and Best Practices Guide
19
Chapter 1
Wire S-Link to terminals
1 and 2 on baseplate
To Rest of the
MS/TP Network
Controller
S-Link Jack
MN-Sx
Sensor
6
COM
SLK
5
SLD (SHLD)
1
S-Link 3
MS/TP 1
Shield
_
2
4
MS+ (MSTP+)
+
MS- (MSTP-)
MS/TP Jack
1
2
MS/TP wiring of controller to sensor screw terminals
is optional.
Note: To preserve the integrity of the network, the
MS/TP network wiring connecting a MicroNet
BACnet controller to an MN-Sx sensor must be run
to the sensor and back, in daisychain fashion. A
wire “spur” must not be used to connect the sensor
to the controller.
2
Observe consistent polarity when wiring.
3
S-Link wiring is not polarity-sensitive.
4
Tie the MS/TP shields together at the sensor.
3
4
2
To Rest of the
MS/TP Network
Wire MS/TP to terminals
3 and 4 on baseplate
5
MS/TP shields must be connected to the SLD (or SHLD)
terminal of all MicroNet BACnet controllers.
6
S-Link communications is not supported in the
MNB-1000-15 remote I/O module.
Figure–1.13 Sensor Link (S-Link) Connection.
Velocity Pressure Input
MNB-V1 and MNB-V2
Table–1.15 lists specifications for the velocity pressure inputs on MNB-Vx
controllers.
Table–1.15 Velocity Pressure Input, on MNB-V1 and MNB-V2.
Input
Control Range
Over Pressure
Withstand
Accuracy
Sensor Type
Tubing Connections
Tubing Length
Characteristics
0.004 to 1.5 in. of W.C. (0.996 to 373.5 Pa)
±20 in. of W.C. (4.980 kPa)
±5% at 1.00 in. of W.C. (249.00 Pa) with laminar flow at
77 °F (25 °C) and suitable flow station.
Self-calibrating flow sensor (differential pressure).
Barb fittings for 0.170 in. I.D. (4.3 mm I.D.) FRPE
polyethylene tubing or 0.25 in. O.D./0.125 in. I.D. (6.4 mm
O.D./3.2 mm I.D.) Tygon® tubing (high and low pressure
taps).
5 ft (1.52 m) maximum, each tube.
20 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
MicroNet Digital Wall Sensors
Each MicroNet BACnet controller supports a single MN-Sx digital wall
sensor. 12 sensor models are presently available, six sensing zone
temperature and six sensing both zone temperature and humidity. These
range from a sensor-only model to one with seven pushbuttons and an LCD
screen. Table–1.16 provides a feature summary of the MN-Sx sensors.
Note: S-Link communications is not supported in the MNB-1000-15 remote
I/O module.
Table–1.16 MicroNet Sensors.
Sensor Model
MN-S1
MN-S1HT
Features
Sensor Model
MN-S2
MN-S2HT
No buttons
• Sensor only.
Its primary function is to provide room
temperature or humidity sensing values
to the controller via the Sensor Link.
One button
• Sensor (as in MN-S1).
• Override key with LED indicator, to
allow the timed override of unoccupied
to occupied modes of operation.
MN-S4
MN-S4HT
MN-S3
MN-S3HT
Three buttons
• MN-S2 features—Sensor; Override key
with LED indicator.
• 3-digit LCD for showing (typically) the
current temperature.
• Up and Down keys to allow adjustment
of the current setpoint.
MN-S4-FCS
MN-S4HT-FCS Six buttons
• Larger LCD capable of showing up to
four possible temperature, humidity,
and function displays
• Up and Down keys for setpoint
adjustment.
• Three fan speed selection keys:
– High Fan Speed
– Medium Fan Speed
– Low Fan Speed
• Fan On / Off / Auto key.
F-27360-11
Features
MN-S5
MN-S5HT
Six buttons
• MN-S3 features—Sensor; Override key
with LED indicator; LCD temperature,
humidity, and function display (larger
than in MN-S3, capable of showing up
to four possible displays); Up and
Down keys for setpoint adjustment.
• These “sub-base” functions:
– Mode key allowing two
Heat/Cool/Auto/Off modes.
– Fan key to control fan operation or
speed.
– Setpoint key to select up to four
Heat/Cool setpoints.
Seven buttons
• MN-S4 features—Sensor; Override key
with LED indicator; larger LCD capable
of showing up to four possible
temperature, humidity, and function
displays; Up and Down keys for
setpoint adjustment; Mode key, Fan
key, and Setpoint key “sub-base”
functions.
• Emergency Heat key with LED
indicator for emergency heat activation
or indication (Heat Pump applications).
MicroNet BACnet Wiring, Networking, and Best Practices Guide
21
Chapter 1
Common Sensor
Features
An MN-Sx sensor communicates with (and is powered by) two Sensor Link
(S-Link) terminals on a MicroNet controller — it does not consume a typical
I/O point. The S-Link connection between the sensor and the controller can
use low-cost, twisted-pair wire up to 200 ft (61 m), and is not polarity
sensitive. All MN-Sx sensor models also include an MS/TP jack for a
convenient means of connecting a network tool, such as a Work Place Tech
Tool PC, to the BACnet network.
Under each MN-Sx sensor’s detachable cover is a pre-wirable baseplate
and a removable electronic assembly (Figure–1.14). The same baseplate is
used in all MN-Sx sensor models.
Pre-wirable Sensor
Baseplate
S-Link Screw Terminals
(1 and 2)
Removable Electronic
Assembly (contains
temperature sensor)
MS/TP Jack
Figure–1.14 MN-Sx Sensor Pre-Wirable Baseplate and Electronic Assembly.
Note: MN-Sx sensors have no independent intelligence. This means any
MN-Sx sensor’s behavior is defined by how the application control logic has
been engineered, compiled, and downloaded into the MicroNet controller.
This allows replacement of a sensor without need of additional
programming.
Keypad Icons
Depending on the sensor model used and the control application, various
keypad buttons allow the sensor user to select or perform different functions.
Table–1.17 MicroNet Sensor Keypad Icon Definitions.
+
+
Setpoint
Up
Override
!
Emergency Heat
Down
Fan On/Off or Speed
Mode
Fan Speed (MN-S4-FCS) Hi,
Med, Low
Fan On/Off Auto (MN-S4-FCS)
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I/A Series BACnet Hardware
LCD Icons
Sensor models featuring an LCD typically show the current zone
temperature as a default display. The MN-S4, MN-S4HT, MN-S5, and
MN-S5HT models can also display selected icons, as shown in
(Table–1.18). These icons represent status items, depending on keypad
input and the current control application.
Table–1.18 MicroNet Sensor LCD Icon Definitions.
Diagnostic
Functions
°F
Degrees F
Fan
Cool
°C
Degrees C
Fan Speed Hi
On
%
Relative Humidity
Fan Speed Med
Outdoor Air
Fan Speed Lo
Off
Fan
Heat
Unoccupied
AUTO Auto
MN-S3, S3HT, S4, S4HT, S4-FCS, S4HT-FCS, S5, and S5HT sensors
provide access to additional diagnostic data through the sensor keypad. This
Diagnostic Mode data is displayed on the LCD screens of these sensors.
See Figure–1.15 (MN-S5 and MN-S5HT) and Figure–1.16 (MN-S4-FCS and
MN-S4HT-FCS) for descriptions of the various elements of the keypad and
LCD display.
LCD. The top area
displays analog values,
such as temperature
and setpoints.
1
°F
°C
%
The MN-S4, S4HT,
S5, and S5HT can
show additional
icons in this area. 1
AUTO
+
Setpoint, Mode,
and Fan buttons on
the MN-S4, S4HT,
S5, and S5HT.
Emergency Heat button
and LED (MN-S5 and
MN-S5HT only).
+
!
Up/Down buttons on MN-S3,
S3HT, S4, S4HT, S4-FCS,
S4HT-FCS, S5, and S5HT
are used to adjust setpoints
and cycle through LCD icon
displays.
Override button and
Override LED. MN-S2,
S2HT, S3, S3HT, S4,
S4HT, S4-FCS,
S4HT-FCS, S5, and
S5HT have this feature.
1 The icons displayed in the LCD are dependent upon the sensor model used,
the mode the controller is in, and the sensor's configuration in WP Tech. Not all
icons are shown in this illustration.
Figure–1.15 MN-S5 and MN-S5HT Keypad and LCD
(Most LCD Icons Shown Illuminated).
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Chapter 1
LCD. The top area
displays analog values
such as temperature,
humidity, and setpoints. 1
°F
°C
%
The MN-S4-FCS
and S4HT-FCS can
show additional
icons in this area. 1
AUTO
+
Fan speed buttons,
used to set High,
Medium and Low
speed.
Up/Down buttons are
used to adjust setpoints
and cycle through LCD
icon displays.
-
Fan - On/Off
Auto (optional)
and Fan
indication LED.
1 The icons displayed in the LCD are dependent upon the mode the controller is
in and the sensor's configuration in WP Tech. Not all icons are shown in the
illustration.
Figure–1.16 MN-S4-FCS and MN-S4HT-FCS Keypad and LCD
(Most LCD Icons Shown Illuminated).
The LCD screen includes separate displays (frames) for the MicroNet
controller’s:
• Subnet and Node Address
Note: Subnet will always display Ø (null), and the node address will
reflect the address DIP switch setting.
• Errors–Not Supported
• Alarms–Not Supported
• Temperature and Relative Humidity Offsets
With the exception of the Temperature or Relative Humidity Offset,
Diagnostic Mode data is view only. The Temperature or Relative Humidity
Offset is adjustable and applies only to the integral temperature or humidity
sensor in the MN-Sx sensor.
See the I/A Series MicroNet Sensors General Instructions, F-26277, for
detailed information on the features and operation of MN-Sx sensors,
including the Diagnostic Mode.
24 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Communications Wiring
Communications wiring includes a connection between the controller and a
MicroNet MN-Sx Sensor via the S-Link, and a connection between the
controller and the MicroNet BACnet Network. Optionally, an MS/TP jack on
the MN-Sx sensor allows a PC with a network tool, such as WP Tech, to be
connected to the BACnet network.
Caution:
• Be sure to observe proper polarity when wiring the controller’s MS/TP
terminals to the MN-Sx Sensor’s wall plate. See Figure–1.13.
• To preserve the integrity of the network, the MS/TP network wiring
connecting a MicroNet BACnet controller to an MN-Sx sensor must be
run to the sensor, then to the next controller, in daisy-chain fashion. A
wire “spur” or “tee” must not be used to connect the sensor to the
controller.
• Communication wire pairs must be dedicated to MN-Sx (S-Link) and
MicroNet BACnet network communications. They cannot be part of an
active, bundled telephone trunk.
• When wiring the MNB-300 or MNB-1000 controller, or the MNB-1000-15
remote I/O module, provide enough strain relief (slack) in the wires to
allow full range of movement for the input and output boards.
• Shielded cable is required for MS/TP network wiring and ADI or remote
I/O network wiring.
• Shielded cable is not required for S-Link wiring.
• If the cable is installed in areas of high RFI/EMI, the cable must be in
conduit.
• The cable’s shield must be connected to earth ground at one end only.
Shield must be continuous from one end of the trunk to the other.
Intermixing of
Cables
Placing certain types of communications and power wiring in close proximity
to each other can result in communications errors. To prevent this when
running cables, you must note the combinations of wiring that may be
intermixed and, when close placement is not recommended, ensure that
there is sufficient separation between them. The combinations of wiring that
are allowed to intermix are summarized in Table–1.19.
Note:
• The term, “intermix,” is used here to refer to the placement of wiring in
close proximity to each other. The placing of wiring in the same conduit,
or bundling the wiring together, are examples of extremely close
placement.
• Observe the correct shielding of cables to prevent communications
problems such as those that may result from the intermixing of certain
wiring types.
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Chapter 1
Table–1.19 Allowed Wiring Combinations for Intermixing
Wiring
S-Link
MS/TP
ADI or Remote I/O
UI, DI, UO
DO
Class 2 24 Vac
S-Link
MS/TP
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
Yes
Yes
ADI or
Remote I/O
Yes
Yes
Yes
No
Yes
Yes
UI, DI, UO
DO
Yes
No
No
Yes
No
No
No
Yes
Yes
No
Yes
Yes
Class 2
24 Vac
No
Yes
Yes
No
Yes
Yes
The following paragraphs detail the conditions under which wiring can be
intermixed, including placement in the same conduit.
Sensor Link (S-Link) Wiring
Observe the following when laying S-Link wiring.
Note: Refer to Table–1.19 for a summary of the types of wiring that may be
placed in close proximity to each other, such as when running wiring through
a common conduit.
• Do not intermix S-Link wiring with DO wiring or Class 2 AC power wiring,
especially in the same conduit.
• The S-Link wiring between an MN-Sx sensor and a MicroNet controller
can be intermixed with the ADI or remote I/O network wiring, or the
MicroNet BACnet MS/TP wiring, including placement in the same
conduit, so long as they are separate cables.
• S-Link wiring can be intermixed with UI, UO, and DI wiring, including its
placement in the same conduit.
MicroNet MS/TP Network Wiring
Observe the following when laying MicroNet MS/TP network wiring.
Note: Refer to Table–1.19 for a summary of the types of wiring that may be
placed in close proximity to each other, such as when running wiring through
a common conduit.
• Do not intermix MS/TP wiring with UI, UO, or DI types of wiring.
• The MicroNet BACnet MS/TP wiring can be intermixed with the S-Link
wiring between an MN-Sx sensor and a MicroNet controller, including
placement in the same conduit, so long as they are separate cables.
• The MicroNet BACnet MS/TP wiring can be intermixed with ADI or
remote I/O network wiring or DO wiring, including placement in the same
conduit, so long as they are separate cables.
• BACnet MS/TP network and Class 2 AC power wiring can be intermixed
(including placement in the same conduit), provided they are separate
cables, and the MS/TP wire is properly shielded and meets the
requirements stated in "Cable Specifications" on page 29.
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ADI and Remote I/O Network Wiring
Observe the following when laying ADI or remote I/O network wiring.
Note: Refer to Table–1.19 for a summary of the types of wiring that may be
placed in close proximity to each other, such as when running wiring through
a common conduit.
• Do not intermix ADI or remote I/O network wiring with UI, UO, or DI
types of wiring.
• The ADI or remote I/O network wiring can be intermixed with the S-Link
wiring between an MN-Sx sensor and a MicroNet controller, including
placement in the same conduit, so long as they are separate cables.
Note that the MNB-1000-15 remote I/O module, itself, does not support
communications with an MN-Sx sensor.
• The ADI or remote I/O network wiring can be intermixed with MicroNet
BACnet MS/TP wiring or DO wiring, including placement in the same
conduit, so long as they are separate cables.
• The ADI or remote I/O network wiring and Class 2 AC power wiring can
be intermixed (including placement in the same conduit), provided they
are separate cables, and the ADI or remote I/O wire is properly shielded
and meets the requirements stated in "Wiring Specifications for ADI or
Remote I/O" on page 31.
I/O Wiring
Observe the following when laying I/O wiring.
Note: Refer to Table–1.19 for a summary of the types of wiring that may be
placed in close proximity to each other, such as when running wiring through
a common conduit.
• Do not intermix UI, UO, or DI wiring with BACnet MS/TP wiring, ADI or
remote I/O network wiring, DO wiring, or Class 2 AC power wiring,
especially placement in the same conduit.
• UI, UO, DI, and S-Link wiring can be intermixed, including placement in
the same conduit, so long as they are separate cables.
• Do not intermix DO wiring with S-Link wiring, especially placement in the
same conduit.
• DO wiring can be intermixed with BACnet MS/TP wiring, ADI or remote
I/O network wiring, or Class 2 AC power wiring, including placement in
the same conduit, so long as they are separate cables.
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Chapter 1
Power Supply Wiring
Observe the following when laying Class 2, 24 Vac power supply wiring.
Note: Refer to Table–1.19 for a summary of the types of wiring that may be
placed in close proximity to each other, such as when running wiring through
a common conduit.
• Do not intermix Class 2 AC power wiring with S-Link wiring or UI, UO, or
DI wiring, especially placement in the same conduit.
• Class 2 AC power wiring can be intermixed with BACnet MS/TP wiring,
ADI or remote I/O network wiring, or DO wiring, including placement in
the same conduit, so long as they are separate cables.
Sensor Link
(S-Link) Wiring
S-Link wiring powers and enables the MN-Sx sensor. The S-Link needs
24 gauge (0.51 mm) or larger, twisted pair, voice-grade telephone wire. The
capacitance between conductors cannot be more than 32 pF per foot
(0.3 m). If shielded cable is used, the capacitance between any one
conductor and the others, connected to the shield, cannot be more than
60 pF per foot (0.3 m). Maximum wire length is 200 ft. (61 m).
Note:
• Each MicroNet BACnet controller supports one MicroNet Sensor
(MN-Sx). Note, however, that the MNB-1000-15 remote I/O module does
not support communications with a MicroNet Sensor.
• S-Link wiring between the sensor and the controller is not polarity
sensitive.
• Refer to "Intermixing of Cables" on page 25 for a discussion of when
S-Link wiring may share conduit with other types of wiring.
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MicroNet MS/TP
Network Wiring
Caution:
• Before terminating the communications (MS/TP) wiring at the controller,
test the wiring for the presence of a 24 Vac or 120 Vac voltage signal. If
present, do not terminate the wiring at the controller’s MS/TP terminals.
Doing so will damage the transceiver chip, rendering the controller
unable to communicate. Instead, take corrective action before
terminating the controller.
• Polarity must be observed for all MS/TP wiring within the MicroNet
BACnet network.
• The MS/TP cable’s shield must be connected to earth ground (GND) at
one end only, to prevent ground currents. Shield must be continuous
from one end of the trunk to the other.
• To preserve the integrity of the network, the MS/TP network wiring
connecting a MicroNet BACnet controller to an MN-Sx sensor must be
run to the sensor, then to the next controller, in daisy-chain fashion. A
wire “spur” or “tee” must not be used to connect the sensor to the
controller.
• Refer to "Intermixing of Cables" on page 25 for a discussion of when
BACnet MS/TP network wiring may share conduit with other types of
wiring.
See Chapter 2, Networking Practices, to design a MicroNet BACnet
network, including recommended topologies. Refer to Appendix A for
BACnet Best Practices.
Cable Specifications
Low capacitance cable is required for high baud rates and high controller
counts. For this reason, all new installations should use a low-capacitance
cable.
Note: Low-capacitance cables are not available in wire sizes larger than
22 AWG (0.326 mm2).
Cable for wiring an I/A Series MS/TP network shall meet the following
specifications:
• Use shielded, twisted-pair cable with characteristic impedance between
100 and 130 ohm. The shield may be either a foil- or braid-type, and
should shield a single pair of conductors.
• Distributed capacitance between conductors shall be less than 15 pF/ft
(49 pF/m).
• Distributed capacitance between the conductors and the shield shall be
less than 30 pF/ft (98 pF/m).
• The maximum recommended length of an MS/TP segment is 4000 ft
(1200 m), using the cables listed in Table 1.20, on page 30.
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Chapter 1
Approved Cable Types
The stranded, twisted-pair cables listed in Table–1.20 are recommended for
wiring a MicroNet BACnet MS/TP network.
Table–1.20 Recommended BACnet MS/TP Cable Types.
Baud Rate
No. of
Devicesa
Cable
AWG Plenum(mm2) Ratedb
24
(0.205)
24
Belden 82641
(0.205)
Belden 8641
19,200
or Less
32 Devices
or Less
Belden 82502
76,800
or Less
24
(0.205)
Connect-Air
W241P-2000F
24
128 Devices Connect-Air (0.205)
or Less
W241P-2000S
24
Belden 89841
(0.205)
Electrical Specifications
Capacitance @1 kHz
Cond. DC
Resis. per
Cond-Cond Cond-Shield 1000 ft
Oper.
Temp.
No
22.0 pF/ft
(73 pF/m)
42.0 pF/ft
(140 pF/m)
25 ohm
-4 to +176 °F
(-20 to +80 °C)
Yes
31.0 pF/ft
(103 pF/m)
59.0 pF/ft
(197 pF/m)
24 ohm
Yes
25.0 pF/ft
(83 pF/m)
45.0 pF/ft
(150 pF/m)
24 ohm
Yes
11.4 pF/ft
(38 pF/m)
n/a
27 ohm
+302 °F max.
(+150 °C max.)
Yes
12.0 pF/ft
(40 pF/m)
22.0 pF/ft
(73 pF/m)
24 ohm
-94 to +392 °F
(-70 to +200 °C)
+32 to +140 °F
(-0 to +60 °C)
+32 to +140 °F
(-0 to +60 °C)
a. The length of a wiring segment must be 4000 ft (1200 m) or less.
b. Use plenum-rated cable for operating temperatures less than -4 °F (-20 °C).
30 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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ADI and Remote I/O
Module Network
Wiring
Caution: Observe the following requirements for wiring between an
MNB-1000 and an ADI panel or remote I/O module.
• Before terminating the wiring at the controller, test the wiring for the
presence of a 24 Vac or 120 Vac voltage signal. If present, do not
terminate the wiring at the controller’s terminals used for the ADI or
remote I/O network. Doing so will damage the transceiver chip,
rendering the controller unable to communicate. Instead, take corrective
action before terminating the controller.
• Polarity must be observed.
• The cable’s shield must be connected to earth ground (GND) at one end
only, to prevent ground currents. Shield must be continuous from one
end of the trunk to the other.
• Refer to "Intermixing of Cables" on page 25 for a discussion of when
ADI or remote I/O module network wiring may share conduit with other
types of wiring.
See Chapter 2, Networking Practices, to design a MicroNet BACnet
network, including recommended topologies. Refer to Appendix A for
BACnet Best Practices.
Wiring Specifications for ADI or Remote I/O
Wiring for an ADI or remote I/O module EIA-485 (formerly RS-485) network
shall meet the following specifications:
• Use shielded, twisted-pair cable with characteristic impedance between
100 and 130 ohm.
• Distributed capacitance between conductors shall be less than 15 pF/ft
(49 pF/m).
• Distributed capacitance between the conductors and the shield shall be
less than 30 pF/ft (98 pF/m).
• Foil or braided shields are acceptable.
• The maximum recommended length of an ADI or remote I/O wiring
segment is 4000 ft (1200 m), using the cables listed for “76,800 or Less”
baud rate in Table 1.20, on page 30.
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Chapter 1
I/O Wiring
I/O connections include universal inputs, universal outputs, digital inputs,
and digital outputs. See Figure-1.1, Figure-1.2, Figure-1.3, Figure-1.5, and
Figure-1.6 for wire terminal information.
Caution: If shielded cable is used, connect only one end of the shield to the
common terminal at the controller.
Universal Inputs (UI), Universal Outputs (UO), and Digital Inputs (DI)
Caution:
• Input and output devices cannot share common wiring. Each connected
device requires a separate signal and return conductor.
• Refer to "Intermixing of Cables" on page 25 for a discussion of when UI,
UO, and DI wiring may share conduit with other types of wiring.
Note: If maximum closed switch voltage is not more than 1.0 V and
minimum open switch voltage is at least 4.5 V, then solid state switches may
be used for a UI or a DI.
UI, UO, and DI wiring needs at least AWG #24 (0.205 mm2), twisted pair,
voice grade telephone wire. The capacitance between conductors cannot be
more than 32 pF per foot (0.3 m). If shielded cable is used, the capacitance
between any one conductor and the others, connected to the shield, cannot
be more than 60 pF per foot (0.3 m). Table–1.21 provides wiring
specifications.
Table–1.21 UI, UO, and DI Wiring Specifications.
Connection
UI, UO, and DI
Gauge
AWG (mm2)
18 (0.823)
20 (0.518)
22 (0.326)
24 (0.205)
Maximum Distance
ft (m)
300 (91)
200 (61)
125 (38)
75 (23)
Refer to Figure–1.7, Figure–1.8, and Figure–1.9, respectively, for examples
of UI, UO, and DI connections.
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Digital Outputs (DO)
Caution:
• The Triac (digital) outputs on MicroNet BACnet controllers are not
protected against short circuits. Take necessary precautions to protect
these outputs against short circuits.
• DO terminals accept up to one AWG #14 (2.08 mm2) or two AWG #18
(0.823 mm2) or smaller wires. The selected wire gauge must be
consistent with the load current rating.
• MicroNet BACnet controllers are Class 2 devices. Each digital (Triac)
output on an MNB-300 controller, MNB-1000 controller, or MNB-1000-15
remote I/O module can support up to 12 VA at 24 Vac, 50/60 Hz, pilot
duty. On MNB-V2 and MNB-70 controllers, digital (Triac) outputs DO1
plus DO2 can support a combined total of 24 VA at 24 Vac, 50/60 Hz,
pilot duty, while DO3 can support up to 12 VA.
• Refer to "Intermixing of Cables" on page 25 for a discussion of when DO
wiring may share conduit with other types of wiring.
If the transformer is sized correctly, the 24 Vac Class 2 power source may be
used for load power. See Figure–1.17 for a diagram showing this with an
MNB-300, MNB-1000, or MNB-1000-15.
Note: With the MNB-V2 and MNB-70, AC voltage to Triacs is sourced from
the controller. This is different from the MNB-300 and MNB-1000 controllers
and the MNB-1000-15 remote I/O module, where AC voltage is sourced
externally. Refer to Figure–1.10 and Figure–1.11 for examples of Triac (DO)
connections.
24 H
24 G
GND
Primary
24 Vac
Class 2
Transformer
TO1
Load1
C1
TO2
Load2
C2
TOx
Loadx
Cx
Figure–1.17 MNB-300, MNB-1000, and MNB-1000-15—Sharing Common
Transformer Between DO Loads and Controller Power.
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Chapter 1
Power Supply Wiring
Ensure that MNB-70, MNB-300, and MNB-Vx controllers and the
MNB-1000-15 remote I/O module have appropriate 24 Vac power, taking
note of the following cautions.
Caution:
• Very important! When powering multiple Class 2 devices from the
same Class 2 power transformer, polarity must be observed (24H
connected to 24H, and 24G connected to 24G).
• MicroNet BACnet controllers and remote I/O module are Class 2-only
devices and must be connected to a Class 2 source. Class 2 circuits
must not intermix with Class 1 circuits.
• The MNB-70, MNB-300, and MNB-Vx controllers and the MNB-1000-15
remote I/O module contain a non-isolated half-wave rectifier power
supply and must not be powered by transformers used to power other
devices containing non-isolated full-wave rectifier power supplies. Note
that this precaution does not apply to the MNB-1000, whose IO are fully
isolated from its power supply input. Therefore, an MNB-1000 can be
powered with the same transformer used to power MNB-70, MNB-300,
and MNB-Vx controllers and the MNB-1000-15 remote I/O module.
Refer to EN-206, Guidelines for Powering Multiple Devices from a
Common Transformer, F-26363, for detailed information.
• Use a Class 2 power transformer supplying a nominal 24 Vac, sized
appropriately for the controller (16 VA for MNB-300, 15 VA for MNB-70
and MNB-Vx, 50 VA for MNB-1000, and 16 VA for MNB-1000-15) plus
the anticipated DO loads. The supply to the transformer must be
provided with a breaker or disconnect. In European Community,
transformer must conform to EN 60742.
• The Class 2 power transformer may be used to power multiple Class 2
powered devices, provided that the transformer is properly sized to
power all equipment simultaneously and all devices contain the same
type of rectifier power supplies or internal isolation.
• The transformer frame must be grounded.
• Refer to "Intermixing of Cables" on page 25 for a discussion of when
Class 2 power wiring may share conduit with other types of wiring.
Where power is derived from a central transformer, ensure that transformer
is appropriately sized for the required VA with adequate margin and that the
power wiring length is minimized and the appropriate wire size utilized to
minimize line drops. Adequate transformer power margin should be allowed
so that fluctuations of the primary transformer voltage or fluctuations in the
secondary loads do not cause low voltage power conditions as seen at the
24 Vac input to the controllers.
The MNB-xxxx series controllers contain circuitry that is designed to protect
the integrity of the embedded flash memory under low-voltage or
questionable input voltage conditions. In the event of a controller-perceived
low-voltage condition, the controller will set a read-only flag and lock out all
writes to memory, as well as turn off controller outputs. The read-only flag
can be easily viewed from the WorkPlace Commissioning Tool (WPCT)
34 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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I/A Series BACnet Hardware
under the “Device Properties” and will indicate the controller status as
“Operational, Read-Only.” The Read-Only status can help serve as an
indicator that the input voltage to the controller may be questionable.
Note: The MNB-1000-15 remote I/O module also features protection for its
embedded flash memory. When a module detects a low-voltage condition, or
questionable input voltage conditions, it locks out all writes to memory and
turns off its outputs. However, because the remote I/O module is mapped as
an extension of the MNB-1000 controller’s I/O points, not as a separate
device, it does not set a read-only flag. Instead, the WPCT simply shows the
module as offline, and all its inputs will be “NA.”
Attention should also be paid to the wire distance between the central
transformer and the secondary loads, especially in the case of half-wave
input devices like the MNB-70, MNB-V series and MNB-300 controllers and
the MNB-1000-15 remote I/O module. With half-wave type input devices,
significant AC input current spikes can occur during the positive half-cycle of
the AC input. Large resistances due to the wire lengths can cause significant
voltage drops as seen from the controller AC input. In extreme cases, the
controller may enter the read-only mode at apparent AC voltages exceeding
20 Vac due to the asymmetrical nature of the AC input voltage waveforms. In
these cases, reducing the load on the transformer, reducing the wire length
between the controller and the transformer, and using higher current rated
wire will correct the problem.
Note:
• Power wiring terminals accept one AWG #14 (2.08 mm2) or up to two
AWG #18 (0.823 mm2) wires.
• Power wiring can be intermixed with DO wiring.
• Twisted or untwisted cable can be used for power wiring.
• To preserve the integrity of the network, the MS/TP network wiring
connecting a MicroNet BACnet controller to an MN-Sx sensor must be
run to the sensor and back, in daisychain fashion. A wire “spur” must not
be used to connect the sensor to the controller.
Figure-1.18, Figure-1.19, and Figure-1.20 are acceptable wiring
configurations.
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Chapter 1
To Rest of the
MS/TP Network
Primary
24 Vac
Secondary
Class 2
Black
White
Green (Ground)
To Controller
or Remote
I/O Module
From
Transformer
2
1
2
3
Optional connection provides local access to
the MS/TP network.
Ground the frame of the transformer to a
known ground.
S-Link is not supported in the MNB-1000-15
remote I/O module.
1
Controller
MNB-70
MNB-300
MNB-1000
MNB-V1
MNB-V2
MS/TP
S-Link
Remote I/O Module
MNB-1000-15
From
Transformer
To Rest of the
MS/TP Network
3
24H
24G
GND
MN-Sx
Sensor
MS/TP
24H
24G
GND
IO+
IOSLD
To Rest of
the Remote
I/O Network
From
MNB-1000
Remote I/O
Network
Figure–1.18 Single Controller or I/O Module Powered from a Separate Class 2 Power Source.
36 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
I/A Series BACnet Hardware
Primary
To Other
MNB-70, MNB-300,
MNB-1000, and MNB-Vx
Controllers
24 Vac
Secondary
Class 2
9
To Rest of the
MS/TP Network
MNB-70
MNB-300
MNB-1000
MNB-V1
MNB-V2
Black
White
Green (Ground)
1
2
3
4
5
6
7
8
9
In MS/TP networks, a 120 ohm
±5% EOL resistor must be used
at each end of line. In the case
of an MNB-300 or MNB-1000,
EOL jumpers are provided.
Do not use EOL resistors in
standalone applications that do
not include MS/TP
communications.
MS/TP
Shield
7
S-Link
MN-Sx
Sensor
3
2
4
1
MS- (MSTP-)
MS+ (MSTP+)
SLD (SHLD)
MS/TP
Shield
7
S-Link
24H
24G
GND
MN-Sx
Sensor
MS/TP
2
MNB-1000
MS- (MSTP-)
MS+ (MSTP+)
SLD (SHLD)
MS/TP shields must be
connected to the SLD (or SHLD)
terminal of all MicroNet BACnet
controllers.
Shield
7
Do not make an MS/TP
connection to the sensor at the
end of chain unless an EOL
resistor is used.
At least one set, and no more
than two sets, of network bias
resistors must be present on
each MS/TP network segment,
preferably (but not required to
be) in the middle of the segment.
In MS/TP networks, this requires
an MNB-300, MNB-1000, or
UNC-520 with the appropriate
jumper settings.
Note: Jumper-set MS/TP bias
resistors are built into UNC-520s.
6
1
24H
24G
GND
MNB-70
MNB-300
MNB-1000
MNB-V1
MNB-V2
5
4
MS- (MSTP-)
MS+ (MSTP+)
SLD (SHLD)
Optional connection provides
local access to the MS/TP
network.
Ground the frame of the
transformer to a known ground.
MS/TP shield must be tied to
ground (GND) at a single point
only.
Tie the MS/TP shields together
at the sensor baseplate (there is
no GND terminal at the sensor).
Or to End-Of-Line
Resistor
E
O
L
24H
24G
GND
IO+
IOSLD
2
MNB-70
MNB-300
MNB-1000
MNB-V1
MNB-V2
24H
24G
GND
2
Shield
E
O
L
MS- (MSTP-)
MS+ (MSTP+)
SLD (SHLD)
To Network of
MNB-1000-15
Remote I/O
Modules
5
6
EOL
8
MS/TP
Shield
7
S-Link
MN-Sx
Sensor
To Rest of the
MS/TP Network
Figure–1.19 Multiple Controllers Powered from a Single Class 2 Power Source and
Sharing Communications in a BACnet MS/TP Segment.
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Chapter 1
To Other
MNB-70, MNB-300,
MNB-1000, and MNB-Vx
Controllers
Primary
24 Vac
Secondary
Class 2
E
O
L
Black
White
Green (Ground)
4
MNB-1000-15
24H
IO+ 24G
IO- GND
SLD
To MNB-70, MNB-300,
MNB-1000, or MNB-Vx
Controller
Shield
2
6
To Rest of the
MS/TP Network
Remote I/O
MS/TP
MNB-1000-15
MNB-1000
24H
MS- (MSTP-)
MS+ (MSTP+)
SLD (SHLD)
Shield
IO+ 24G
IO- GND
SLD
Shield
6
5
3
7
IO+
IOSLD
24H
24G
GND
2
1
Remote I/O
MNB-1000-15
24H
Shield
E
O
L
Shield
MS/TP
6
4
To Rest of the
MS/TP Network
1
To Other
MNB-70, MNB-300,
MNB-1000, and MNB-Vx
Controllers
2
3
IO+ 24G
IO- GND
SLD
6
One to eight MNB-1000-15 remote I/O modules
may be connected to a remote I/O network.
Ground the frame of the transformer to a known
ground.
MS/TP or remote I/O shield must be tied to
ground (GND) at a single point only.
4
In remote I/O networks, the EOL resistor must
be set at each end of line. The MNB-1000
controller and the MNB-1000-15 module have a
jumper-set remote I/O EOL resistor for this
purpose.
5
MS/TP shields must be connected to the SLD
(or SHLD) terminal of all MicroNet BACnet
controllers.
3
6
Remote I/O shields must be connected to the
SLD (or SHLD) terminals of the MNB-1000
controller and the MNB-1000-15 remote I/O
module(s).
7
Bias for the remote I/O network is provided by
the permanently enabled, built-in bias resistors
on the MNB-1000 controller. The jumper-set
bias resistors located under the cover of the
MNB-1000-15 remote I/O module are set to
"disabled" at the factory, and must not be used
for this purpose.
Figure–1.20 Multiple Controllers and Remote I/O Modules Powered from a Single Class 2 Power Source and
Sharing Communications in a Remote I/O Network.
38 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
Chapter 2
Networking Practices
This chapter provides an overview of the BACnet protocol and, more
specifically, its implementation in the MicroNet BACnet system. This chapter
then explains how MicroNet BACnet controllers and sensors are configured
for an MS/TP network. The topics covered include:
•
•
•
•
•
•
•
Introduction to BACnet
Architecture Overview
MS/TP Network Configuration
Remote I/O Network Configuration
MS/TP Network Considerations
Other Network Setup Considerations
Network Setup Procedures
Introduction to BACnet
In BACnet systems, BACnet devices use BACnet objects to share data. To
allow this sharing of data, a BACnet network must be properly configured.
On a properly configured network, the BACnet protocol carries data and
uses Ethernet, Internet Protocol (IP), and Master Slave Token Passing
(MS/TP) for network communication. At the device level, MS/TP network
trunks connect individual BACnet compliant controllers.
Refer to Appendix A, BACnet Best Practices, for detailed information related
to BACnet.
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Chapter 2
Architecture Overview
Introduction
As implemented in a TAC I/A Series MicroNet BACnet network, the BACnet
architecture uses one or more networking data link layers to allow
communication among controllers and engineering tools. At the device level,
Master Slave Token Passing (MS/TP) networks can be used to connect up
to 127 MNB-70, MNB-300, or MNB-Vx controllers, or MS/TP tools, to an
MNB-1000 controller (see Table 2.1, on page 42). With 127 devices
connected to an MNB-1000, all 128 MS/TP addresses on the MS/TP
network are used. Similarly, up to 127 devices (MNB-70, MNB-300,
MNB-Vx, MNB-1000, or MS/TP tools) can be connected to each network
trunk of a UNC-520 or ENC-520 network controller, provided sufficient
resources are available within the UNC or ENC (Table–2.1). Multiple BACnet
MS/TP networks can be connected by networking the MNB-1000s and
UNC/ENCs, using BACnet over IP or BACnet over Ethernet. This is referred
to as a BACnet internetwork. In such a configuration, the MNB-1000s and/or
UNC/ENCs manage communication throughout the internetwork and serve
as routers. Engineering tools can be used to manage controllers throughout
an internetwork by connecting them to an MS/TP network trunk or by
connecting to the IP network.
Figure-2.1 shows how a BACnet internetwork is comprised of four or five
individual networks. There are three individual MS/TP network trunks, each
managed by a UNC/ENC or MNB-1000 and running individual BACnet
devices. Ethernet or IP can be used as the networking technology for the
backbone, adding a fourth network. If appropriate for the installation, both
Ethernet and IP can be used on the network backbone. This would add a
fifth network to the internetwork as shown in Figure–2.1.
40 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Networking Practices
PC Workstation
with WorkPlace
Tech Tool Suite
Ethernet and/or IP Backbone
BACnet Internetwork
Optional Port
Bridging to
Additional
MNB-1000
Controllers
BACnet Router:
I/A Series Network
Controller
MSTP NetworkTrunk
BACnet Router:
MicroNet BACnet
MNB-300
Unitary Controller
MicroNet BACnet
MNB-1000 Plant
Controller
AO
BACnet MS/TP
Comm Bus
AO
AO
MicroNet
BACnet
MNB-1000-15
Remote I/O
Modules
MicroNet BACnet
MNB-70
Zone Controller
MicroNet BACnet
MNB-70
Zone Controller
S-Link
Sensor
MicroNet BACnet
MNB-300
Unitary Controller
S-Link
Sensor
MicroNet BACnet
MNB-V1 or V2
VAV Controller
S-Link
Sensor
S-Link
Sensor
S-Link
Sensor
Notebook PC
with WorkPlace
Tech Tool
Software Suite
BACnet MS/TP Communications Bus
MicroNet BACnet
MNB-70
Zone Controller
Remote I/O Communications
S-Link
Sensor
BACnet MS/TP Communications Bus
MicroNet BACnet
MNB-V1 or V2
VAV Controller
BACnet MS/TP Communications Bus
MicroNet BACnet
MNB-1000
Plant Controller
MicroNet BACnet
MNB-V1 or V2
VAV Controller
S-Link
Sensor
Notebook PC
with WorkPlace
Tech Tool
Software Suite
Figure–2.1 BACnet Internetwork
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Chapter 2
MS/TP Network Configuration
The basic TAC I/A Series BACnet configuration is shown in Figure–2.1.
Observe the following networking guidelines, for best operation on your
BACnet MS/TP network trunks.
Physical Limits
Number of Connected Devices
According to EIA-485 Specification
128 devices (including the UNC/ENC-520 or MNB-1000) is the physical limit
of a MicroNet BACnet MS/TP network trunk. This limitation comes from the
EIA-485 (formerly RS-485) specification on which a BACnet MS/TP network
is based. According to this specification, the electrical limit of EIA-485
networks is 32 unit loads per segment (between repeaters), based upon the
loading characteristics of the devices on that segment. However, because
the UNC/ENC-520 and MicroNet BACnet controllers all use 1/4-load
transceivers, four of these devices would together equal one unit load.
Therefore, the actual electrical limit of an MS/TP network trunk comprised of
a UNC/ENC-520 or MNB-1000, plus the MicroNet BACnet controllers
connected to it, is 4 times 32, or 128 total devices.
Note: In terms of the EIA-485 standard, a unit load is based upon a device
that has a EIA-485 transceiver whose load effect is 12 kilohm. The design of
the EIA-485 transceiver on MicroNet BACnet controllers results in a load
effect of 48 kilohm, thus making these controllers 1/4-load devices.
Maximum Number of Devices
Table–2.1 lists the physical limit on the number of devices that can be
connected to an MNB-1000, a UNC-520, or an ENC-520.
Table–2.1 Maximum Number of Connected Devices on MS/TP Trunk.
MicroNet BACnet
Router
Maximum Number of
MS/TP Connections
MNB-1000
UNC-520
1
4
Physical Limit of
Connected Devices
(not including router)
127
508
ENC-520
4
508
Note: The physical limit on the number of connected devices shown in
Table–2.1 does not mean that a UNC-520, an ENC-520, or an MNB-1000
can effectively support that number of devices. There are many logical
factors that can further limit that number. Refer to Logical Limits, below.
Logical Limits
Addressing Limit
The addressing of an MS/TP network trunk is limited to 256 addresses,
numbered 0 to 255. Master devices are restricted to the first 128 addresses
(0 to 127), while slave devices may use any address from 0 to 255. Because
all UNC/ENC-520s and MicroNet BACnet controllers on an MS/TP network
42 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Networking Practices
trunk are master devices, they must be addressed with the first 128
addresses. As such, the address limit is the same as the physical limit of an
MS/TP network trunk.
Limits to Number of Polled Points
Methods for Limiting Polled Points
There are three means for limiting the number of polled points, as described
below.
Note: For additional information related to limiting the number of polled
points, refer to Appendix A, BACnet Best Practices.
PollOnDemand Containers: The first method uses PollOnDemand
containers, which limit the polling to those points that are being queried by
an active GxPage. This means the points are polled if the graphic is being
viewed in a browser, otherwise they do not. Points that must be polled all of
the time (such as schedules), and points that are being logged, do not
qualify for use in PollOnDemand containers.
Number of Devices: The second method is to limit the number of
connected devices, as fewer devices equals fewer polled points.
COV Subscription: The third method is to use COV subscription to create
subscriptions that send notifications to the subscribing device, thereby
limiting the overall number of polled points. COV subscription can be used
for most points that support the Subscribe COV service. However, in the
case of points whose values change quickly, be sure to set the change of
state value appropriately, so that COV notifications are not sent more
frequently than necessary. Refer to Appendix A, BACnet Best Practices for
more information.
Note: The relationship between polled points and COV subscribed points is
not always easy to define. In general, COV subscribed points would not be
considered polled points. However, a UNC/ENC-520 station will poll any
BACnet output or AV priority point, therefore these point types still count as
polled points, even when they are configured as COV subscribed points.
Limits to Resources
Communications through UNC/ENC-520s is further limited by the availability
of Java resources (resource count) and other resources, such as processor
and memory. A shortage of these resources will limit the devices on an
MS/TP network to a number less than the physical limit. Exceeding the
resource limit will negatively affect the UNC/ENC-520s, possibly causing
poor performance and resets (of the UNC/ENCs).
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Chapter 2
Connection to an
MS/TP Network
There are two methods for connecting a PC or notebook computer running
WorkPlace Commissioning Tool (WPCT) or WorkPlace Tech Tool (WP Tech)
5.x to an MS/TP network.
BACnet Ethernet or BACnet/IP
The preferred method is to connect the PC or notebook computer to a LAN
connection, and use BACnet/IP to connect to the BACnet internetwork. The
BACnet internetwork connection routes the BACnet messages to the
BACnet MS/TP network, as needed, through BACnet routers
(UNC/ENC-520s or MNB-1000s). BACnet Ethernet can also be used to
connect to the BACnet internetwork, but communication speed will be
slower.
Controller MS/TP Jack or Sensor S-Link Jack
The second method connects the PC or notebook computer directly to the
MS/TP network, either at the MS/TP jack on a MicroNet BACnet controller,
or at the MS/TP jack of an S-Link sensor, provided it is connected to the
MS/TP trunk. This type of connection requires a USB-to-MS/TP converter or
EIA-232-to-MS/TP converter, depending on the port used on the computer.
Caution: A notebook computer connected to the MS/TP jack on an S-Link
Sensor creates a Tee connection into the daisy-chained MS/TP network
trunk. To minimize disruption of MS/TP trunk communications, the cable
connecting the notebook to the MS/TP trunk should be as short as possible.
Remote I/O Network Configuration
The basic TAC I/A Series BACnet configuration is shown in Figure–2.1 on
page 41. The system illustrated there includes a remote I/O network,
connected under an MNB-1000. A remote I/O network of one to eight
MNB-1000-15 remote I/O modules can be connected to an MNB-1000 to
greatly expand its I/O count.
Observe the following networking guidelines, for best operation on your
remote I/O network.
Connections
When connecting one or more MNB-1000-15 remote I/O modules to an
MNB-1000 controller, observe the following:
• Be sure to connect the remote I/O network wiring to the MNB-1000
controller’s remote I/O port, not the MS/TP port or the MS/TP jack (see
Figure–1.5 on page 12).
• No other types of devices other than MNB-1000-15 remote I/O modules
may be connected to a remote I/O network, including S-Link sensors,
commissioning and maintenance tools such as the WorkPlace Tech Tool
Suite, etc.
44 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Physical Limits
Number of Connected Devices
According to EIA-485 Specification
The remote I/O network is based on the same EIA-485 (formerly RS-485)
specification as the MS/TP network. However, because the number of
MNB-1000-15 remote I/O modules that are allowed to be connected to an
MNB-1000 is limited to eight devices, there is no danger of exceeding the
EIA-485 limit.
Maximum Number of Remote I/O Modules
A maximum of eight MNB-1000-15 remote I/O modules may be connected
to an MNB-1000 controller.
Logical Limits
Addressing Limit
Each remote I/O module is equipped with a DIP switch for setting its address
on the remote I/O network (Figure–2.2). The addressing of a remote I/O
network is limited to nine addresses, numbered 0 to 8. The MNB-1000
controller’s local I/O is already assigned the address “0,” while the
MNB-1000-15 modules are assigned addresses “1” through “8.”
DIP Switch for Addressing
Remote I/O Module
Least
Significant
Bit (LSB)
O 1
N
2 3 4 5 6 7 8
Most
Significant
Bit (MSB)
Note: This example shows
the address set to "5."
Figure–2.2 DIP Switch Address Example.
Use Table–2.2 to calculate the DIP switch value for remote I/O module
addressing.
Table–2.2 DIP Switch Value for Remote I/O Modules
Switch
Number
Value to add
if switch is ON
Switch
Number
Value to add
if switch is ON
1 (LSB)
1
5
Always OFF
2
2
6
Always OFF
3
4
7
Always OFF
4
8
8 (MSB)
Always OFF
For example, when setting the address to 8, you would set switch number 4
(value=8) to ON, while leaving switches 1, 2, and 3 OFF. In another
example, you would set the address to 7 by setting switch numbers 1, 2, and
3 to ON (value=1+2+4=7), while leaving switch 4 OFF.
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Chapter 2
Note:
• Addresses assigned to the remote I/O modules must be consecutive.
That is, no addresses may be missed or duplicated. They are also
required to start with “1,” as enforced by WP Tech. If there are only 2
modules connected, they must be addressed as “1” and “2.”
• The addresses assigned to the MNB-1000-15 remote I/O modules are
used only within the remote I/O network. These modules are transparent
to the MS/TP network to which the MNB-1000 is connected. For all
intents and purposes, the controller and its modules can be viewed,
simply, as an MNB-1000 controller with expanded I/O.
Increased I/O Count
The addition of MNB-1000-15 remote I/O modules can greatly increase the
number of I/O points of an MNB-1000 controller. Therefore, when adding a
remote I/O network to an MNB-1000, it is especially important to take into
account the increased I/O count when taking steps to limit the number of
polled points on an MS/TP network. Refer to "Limits to Number of Polled
Points" on page 43.
MS/TP Network Considerations
Master and Slave
Devices
On a BACnet MS/TP network, MicroNet BACnet controllers operate as
master devices only. Valid DIP switch settings for these master controllers
are 0-127.
Physical
Addressing
Each controller on an MS/TP network trunk is initially identified by a unique
address. The physical address is defined by the network number of the
MS/TP network trunk into which the controller is connected, plus the
controller’s address, which is set with the DIP switch on the controller.
Procedures for assigning an MS/TP network number to an MS/TP network
trunk under the control of a UNC-520 are provided in the BACnet Integration
Reference. Similar procedures for an ENC-520 are provided in the
NiagaraAX BACnet Guide and the NiagaraAX Networking and IT Guide.
Procedures for assigning an MS/TP network number to an MNB-1000 are
found in the Commissioning Tool and Flow Balance Tool Users Guide,
F-27358.
Required Configuration
The DIP switch must be set on every controller that is added to an MS/TP
network trunk. This number must be unique on that particular MS/TP
network trunk but can be used on another internetworked MS/TP network
trunk. For example, referring to Figure–2.1, each of the three MS/TP
network trunks shown could use the DIP switch setting of 5 (Figure–2.2).
However, the same address (DIP switch setting) cannot be used on two
controllers that are on the same MS/TP network trunk. Note that the least
significant bit on the DIP switch is switch 1, the left-most switch.
46 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Use Table–2.3 to calculate the DIP switch value for physical addressing.
Take, for example, that the address must be set to 16. To do so, you would
set switch number 5 (value=16) to ON. If the address is to be set to 43,
instead, you would set switches 1, 2, 4, and 6 to ON (value=1+2+8+32=43)
Table–2.3 DIP Switch Value for MS/TP Networks
Switch
Number
Value to add
if switch is ON
Switch
Number
Value to add
if switch is ON
1 (LSB)
1
5
16
2
2
6
32
3
4
7
64
4
8
8 (MSB)
Always OFF
Caution: In order for communication to occur, a unique MS/TP physical
address must be assigned to each controller on an MS/TP network trunk.
• Duplicate addresses on an MS/TP network trunk will result in erratic
behavior, lost tokens, and disrupted communication.
• There is no software tool that will identify duplicate addresses on an
MS/TP network trunk. Typically, if two controllers are set to the same
address, one of the controllers will appear to be missing from the list,
and the address shared by the two controllers will intermittently come
and go from the list.
• Be sure a network wiring diagram is used to assign and record
addresses assigned to the controllers.
Optimization
MS/TP relies on a communication token that is passed among all master
devices on an MS/TP network. Starting at address 0 (zero) the token is
passed, sequentially, to each device on the MS/TP network trunk until it
reaches the device with the greatest address (i.e. Max Master, explained
later in this paragraph). The token then starts again at address 0 and repeats
the cycle. A controller will attempt to pass the token to the address that is
one greater than its own. If no device occupies that address, the sending
controller tries the next address. It continues searching sequential
addresses until it finds a device to accept the token. For each failed pass
there is a slight delay. Multiple gaps in the sequential addressing can result
in increased communication overhead and decreased network efficiency.
Therefore, addresses should be a contiguous set. Later, using the WPCT, a
value will be set to indicate the greatest valid address on the MS/TP network
trunk. This value is called Max Master. It prevents devices from searching for
valid addresses beyond the greatest valid address. Additional optimization
can be performed later by using the WPCT. Refer to: Appendix A, BACnet
Best Practices and the WorkPlace Tech Tool Release Notes, which is
provided with WorkPlace Tech and is also available in Tech Zone at The
Source (http://source.tac.com/).
MS/TP Address for BACnet Tools
A BACnet tool, connected to an MS/TP network, requires a physical address
for token passing. Leave one address unused, so that it is available for use
by a BACnet tool.
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Chapter 2
Other Network Setup Considerations
Figure–2.3 shows an IP network backbone and an Ethernet network
backbone plus thee MS/TP network trunks forming one BACnet
internetwork. The network backbone can be Ethernet only, IP only, or both.
Ethernet and/or IP Backbone
Optional Port
Bridging to One
or Two Additional
MNB-1000
Controllers
2
3
4
5
1
6
7
7
AO
AO
9
7
8
1
2
Up to 127 controllers can be attached to each trunk of a
UNC-520 or ENC-520 network controller, provided there are
sufficient resources available within the device.
5
Up to 127 controllers can be attached to an MNB-1000.
6
MNB-1000 not configured for routing.
Only one MNB-1000, UNC-520, or ENC-520 may be configured
to route between any two BACnet networks.
7
MS/TP trunks are daisy-chained.
8
A notebook connection to a controller or the MS/TP jack
of an S-Link Sensor is a Tee. It must be as short as
possible to preserve network integrity, and have its own
unique address.
9
One to eight MNB-1000-15 remote I/O modules may be
connected to the remote I/O port of an MNB-1000. The
MNB-1000-15 does not support S-Link.
3
MNB-1000 configured for routing to MS/TP network trunks and
optionally, between Ethernet and IP.
4
A high degree of communications performance may not be
possible if more than one, or possibly two, MNB-1000 controllers
are placed downstream of a bridge. Therefore, no more than
three MNB-1000 controllers should be bridged together.
Figure–2.3 BACnet Networking Restrictions
48 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Networking Practices
Port Bridging
Beginning with Release 1.2, port bridging is enabled on the second Ethernet
port of the MNB-1000 controller. With port bridging, the MNB-1000 acts as a
switch, where messages to and from the LAN are passed from the first
Ethernet port to the second port (Figure–2.4). As such, port bridging is a
convenient method for connecting additional MNB-1000 controllers.
Ethernet and/or IP Backbone
3
Ethernet
Port 0
1
2
Ethernet
Port 1
1
3
5
3
4
4
5
3
3
MicroNet BACnet
MNB-1000
Plant Controller
MicroNet BACnet
MNB-1000
Plant Controller
BACnet MS/TP
Communications Bus
6
BACnet MS/TP
Communications Bus
1
The MNB-1000 contains two Ethernet ports: Port 0 (labeled
"0 Port) and Port 1 (labeled "1 Port").
2
The Ethernet port that is connected to the IP network will
operate at the rate implemented in that network (10 or 100
mbps).
3
When using port bridging, observe the following limitations:
• The maximum distance between MNB-1000 controllers
is 300 ft.
• The throughput through the bridge is limited to 2.5
megabits.
• The throughput of the bridge is limited by the activity
level of the MNB-1000 controller at any given time and
the resources available to process the bridged data.
6
MicroNet BACnet
MNB-1000
Plant Controller
BACnet MS/TP
Communications Bus
4
When port bridging, data is simply passed through an
MNB-1000 from one Ethernet port to the other.
Neither port is designated as the "uplink" or
"downlink" port. Therefore, either of the two Ethernet
ports of an MNB-1000 may be connected to the IP
network, and the other to an adjoining MNB-1000.
5
As a general rule, do not place any customer IT
devices such as computers or routers downstream of
an MNB-1000 used as a bridge. Doing so may
adversely affect the performance of such devices.
6
All devices being port-bridged to an MNB-1000 will
operate at the reduced rate of 2.5 mbps (see note 3).
As a result, a high degree of communications
performance may not be possible if one, or possibly
two, MNB-1000 controllers are placed downstream of
a bridge. Therefore, no more than three MNB-1000
controllers should be bridged together.
Figure–2.4 MNB-1000 Port Bridging.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
49
Chapter 2
Single Path to
Device
BACnet requires that there be no more than one communication path
between two devices anywhere on the BACnet internetwork. More than one
communication path between two devices results in a circular path. Normally
this does not occur because the nature of a properly configured network
does not allow multiple paths between devices. On a BACnet internetwork
that uses both BACnet/IP and BACnet Ethernet, only one UNC/ENC or
MNB-1000 in the internetwork may be configured to route between Ethernet
and IP. If two or more devices are configured to route between BACnet
Ethernet and BACnet/IP, multiple paths between controllers result.
In Figure–2.5 a UNC/ENC routes between BACnet/IP and BACnet Ethernet.
It also routes MS/TP traffic for the BACnet trunk that is attached to it. The
MNB-1000 routes BACnet Ethernet or BACnet/IP for the BACnet trunk that
is attached to it. In this example, the MNB-1000 would be the second device
configured to route between BACnet/IP and BACnet Ethernet, and this is not
permitted. Allowing both the UNC/ENC and the MNB-1000 to serve as
routers violates BACnet internetwork design requirements. This may cause
intermittent communication failures, bandwidth problems, or the interruption
of routing to MS/TP network trunks, as well as the shutdown of BACnet
routing on the UNC/ENC (a self-protective feature).
Ethernet and IP Backbone
IP
Ethernet
IP
Ethernet
One MNB-1000 or I/A
Series Network Controller
can route between
Ethernet and IP.
A second device must
not be configured for
both Ethernet and IP in
a BACnet internetwork.
AO
AO
Figure–2.5 Incorrect Router Configuration
Routers and Network Numbers
In a BACnet internetwork every network is assigned a unique network
number. BACnet routers use the network numbers to route communication
across the internetwork to individual controllers. The network numbers of all
networks connected to a router must be entered into that router using the
setup tool appropriate for the router. The WPCT is used to enter network
numbers in an MNB-1000. In a UNC, WorkPlace Pro is used to enter
network numbers, and Workbench is the tool used for this purpose with the
ENC.
50 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Networking Practices
Network Setup Procedures
The general procedures for setting up a BACnet network are described
below. Follow these procedures to prepare a BACnet network trunk for
logical addressing. After you complete these setup procedures, the WPCT
can be used to configure logical addressing. For logical address
configuration, refer to the Commissioning Tool and Flow Balance Tool Users
Guide, F-27358.
Overview
The general steps are listed below and detailed in the following sections.
1. Perform the physical installation of controllers and cabling.
2. Set the DIP switches on the controllers.
3. Power on the controllers.
4. Use WorkPlace Pro or Workbench to set BACnet service properties of
the UNC/ENC.
Caution: Do not learn controllers until Step 6 has been completed.
This allows traffic to be routed to the MS/TP network trunk(s) attached to
the UNC/ENC and assigns logical addressing to the unit.
5. Use the WPCT to commission the MNB-1000(s) that are connected
directly to the backbone and used for routing, if applicable.
This allows traffic to be routed to the MS/TP network trunk that is
attached to the MNB-1000, and assigns instance numbers to the
MNB-1000.
6. Use the WPCT to assign instance numbers to MNB-1000s that are not
directly connected to the backbone, as well as MNB-70 controllers,
MNB-300 controllers, and MNB-Vx controllers.
Physical
Installation
Install the cabling and controllers following the installation procedures in the
Wiring Guidelines portion of this manual and the following guides:
• MicroNet BACnet MNB-70 Zone Controller Installation Instructions,
F-27456
• MicroNet BACnet MNB-300 Unitary Controller Installation Instructions,
F-27345
• MicroNet BACnet MNB-V1, MNB-V2 VAV Controllers Installation
Instructions, F-27346
• MicroNet BACnet MNB-1000 Plant Controller Installation Instructions,
F-27347
• MicroNet BACnet MNB-1000-15 Remote I/O Module Installation
Instructions, F-27486
• I/A Series UNC-520 Installation Instructions, F-27391
• I/A Series ENC-520 Installation Instructions, F-27416
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MicroNet BACnet Wiring, Networking, and Best Practices Guide
51
Chapter 2
Set the DIP
Switches on the
Controllers
MS/TP Network
A DIP switch must be set on each MNB-70, MNB-300, MNB-1000, MNB-V1,
and MNB-V2. The number must be unique on the MS/TP network trunk in
which the controller is installed but can be repeated elsewhere on the
BACnet internetwork. Refer to "Physical Addressing" on page 46. Follow the
project’s wiring diagram to set the DIP switch on each controller.
Remote I/O Network
A DIP switch must be set on each MNB-1000-15 remote I/O module. Refer
to "Addressing Limit" on page 45. Follow the project’s wiring diagram to set
the DIP switch on each module.
Power on the
MNB-xxxx Devices
Apply power to the MNB-xxxx devices, including all controllers and remote
I/O modules. A status LED will illuminate on each controller or module, to
show operation.
Commission UNCs
and ENCs
For UNC or ENC commissioning instructions, refer to the BACnet Integration
Reference.
Commission the
Controllers
For WPCT details, refer to the Commissioning Tool and Flow Balance Tool
Users Guide, F-27358. Controllers must be commissioned to interoperate
with other BACnet devices. Any remote I/O modules, if present, will be
commissioned together with the MNB-1000 controller to which they are
connected.
52 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Chapter 3
Checkout and Troubleshooting
This chapter provides guidance for troubleshooting MicroNet BACnet
controllers, sensors, and remote I/O modules, including:
• Mechanical Hardware Checkout
• Communications Hardware Checkout
Mechanical Hardware Checkout
Check out the mechanical hardware as follows:
MNB-Vx Controllers Only
1. Verify that both set screws are tightened to the damper shaft.
2. Press and hold the manual override button and rotate the damper by
turning the damper shaft. Verify that the damper moves freely between its
fully open and fully closed positions.
All MNB Controllers
1. Verify that the wiring between the controller and the MicroNet Sensor is
installed according to the job wiring diagram, and to national and local
wiring codes.
Caution:
• Before terminating the communications (MS/TP) wiring at the controller,
test the wiring for the presence of 24 Vac or 120 Vac. If present, do not
terminate the wiring at the controller’s MS/TP terminals. Doing so will
damage the transceiver chip, rendering the controller unable to
communicate. Instead, take corrective action before terminating the
controller.
• Polarity must be observed for all MS/TP wiring within the MicroNet
BACnet network.
• Polarity must be observed for all wiring on remote I/O networks.
• S-Link wiring between the sensor and the controller is not polarity
sensitive.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
53
Chapter 3
2. If the controller is part of a MicroNet BACnet network, verify that the
MS/TP wiring between the controller and other devices is installed in
accordance with the job wiring diagram, following national and local
electrical codes.
3. Connect controllers in a MicroNet BACnet network in daisy-chain
fashion. Be sure that MS/TP polarity, biasing, and termination are
correctly implemented for each network segment.
4. Check for voltage at the COMM wires before setting termination at the
controllers. Be sure voltage is not 24 to 120 Vac.
5. Verify that 24 Vac power is provided from a Class 2 power transformer,
and that power wiring is installed in accordance with the job wiring
diagram, following national and local electrical codes.
6. If multiple devices are powered from a common transformer, verify that
all issues associated with powering multiple devices from a common
transformer have been addressed. In particular, verify that wiring polarity
has been maintained between all connected devices (i.e. 24H connected
to 24H and 24G connected to 24G).
Note: For more information, refer to EN-206, Guidelines for Powering
Multiple Full-Wave and Half-Wave Rectifier Devices from a Common
Transformer, F-26363.
7. Verify that digital outputs are wired according to the job wiring diagram,
and with national and local electrical codes.
8. Make certain that electrical current requirements of the controlled device
do not exceed the rating of the controller’s digital outputs.
Caution: The digital outputs are not internally protected from over-current
or over-voltage conditions.
9. Make certain that the wiring between MNB-1000s and any connected
MNB-1000-15 remote I/O modules is correct.
Note: Connect MNB-1000-15s in a remote I/O network in daisy-chain
fashion. Be sure that polarity, biasing, and termination are correctly
implemented.
54 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Checkout and Troubleshooting
Communications Hardware Checkout
See Figure–3.1 for the locations of controller LEDs and jumpers. Table–3.1
provides a guide for interpreting the LED indications.
MNB-300
Unitary Controller
or
MNB-1000-15
Remote I/O Module
MNB-1000
Plant Controller
TO (DO)
LEDs (8)
6
TO (DO)
LEDs (6)
UO LEDs (3)
6
3
3
XMT
STATUS
4
RCV
8
XMT
7
1
7
STATUS
2
6
MNB-V1 / V2
Controller
6
5
1
Bi-color status LED (all except
MNB-1000-15): green=good; red=fault;
flashing red=bootloader mode.
2
Bi-color status LED (MNB-1000-15):
green=good; slow flashing green=not
configured; fast flashing green=upgrading;
slow flashing red=bootloader mode
(normally 135 sec or less); steady red=not
communicating; fast flashing red=firmware
not compatible.
3
Green data transmission LED.
4
Amber data reception LED.
5
Red/green bi-color AppLED: Can be defined
in the device's application program. Off=0,
Green=1, and Red=2.
6
Internal Triac Switches.
7
EOL and bias jumpers. Bias jumpers not
used in MNB-1000-15 (MNB-1000 provides
bias for remote I/O network).
8
MNB-1000 includes EOL jumper for remote
I/O network.
MNB-70
Controller
1
4
STATUS
MSTP RCV
MSTP XMT
1
4
3
IO
MSTP
AUX
UO
LEDs (8)
Note: Components
are shown in
their approximate
locations.
1
3
RCV
4
STATUS
MSTP RCV
MSTP XMT
Figure–3.1 Location of Controller LEDs and Jumpers.
F-27360-11
MicroNet BACnet Wiring, Networking, and Best Practices Guide
55
Chapter 3
Table–3.1 LED Indications.
MNB-1000-15
MNB-1000
MNB-V1, -V2
MNB-300
MNB-70
Controllers &
Remote I/O Module
Status
Corrective
Action
Indicator
Context
Status LED
Red/green
Power-up
• Blinks red briefly then becomes solid
green.
Indicates: A normal, healthy state.
No action required.
Power-up
• Blinks red during power-up, which
takes 70 to 90 seconds to complete.
When the power-up process
successfully completes, the Status
LED becomes solid green.
Indicates: Normal operation.
No action required.
Contact Schneider Electric
Product Support.
Status
X
X
X
X
Status LED
Red/green
X
Status LED
Red/green
Power-up
• Blinks red for a period of 2 minutes,
then switches to solid red ON.
Indicates: Power-up process has
failed. Controller fault.
X
X
X
Status LED
Red/green
Normal
Operation
• Solid green.
Indicates: A normal, healthy state.
No action required.
X
X
X
Status LED
Red/green
Normal
Operation
• Solid red.
Indicates: A controller fault.
Contact Schneider Electric
Product Support.
Normal
Operation
Wink Mode.
• Blinks red ON for 3 seconds, then
OFF for 1 second, repeatedly for a
period of 20 seconds (default).
No action required.
• The MN-Sx sensor’s Override LED
also blinks (all sensors except MN-S1
and MN-S1HT).
Indicates: Normal operation.
Normal
Operation
Wink Mode.
• Blinks red ON for 1 second, then OFF
for 1 second, repeatedly for a period
of 20 seconds (default).
No action required.
• The MN-Sx sensor’s Override LED
also blinks (all sensors except MN-S1
and MN-S1HT).
Indicates: Normal operation.
X
X
Status LED
Red/green
X
X
Status LED
Red/green
56 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Checkout and Troubleshooting
Table–3.1 LED Indications. (Continued)
MNB-1000-15
MNB-1000
MNB-V1, -V2
MNB-300
MNB-70
Controllers &
Remote I/O Module
Indicator
Context
Status
Corrective
Action
Status (Continued)
X
X
Status LED
Red/green
X
X
X
X
X
X
X
X
F-27360-11
Bootloader Mode.
• Solid red ON at power-up.
Indicates: That the bootloader code
is executing and the CRC test is either
pending or has failed.
• Blinks red ON for 1 second, then OFF
After Flash
for 1 second.
No action required.
Upgrade
Indicates: The bootloader has
passed the CRC test. Continues to
repeat this pattern while the
bootloader waits for a firmware
upgrade or prepares for the jump to
existing firmware.
Bootloader Mode.
• Continues to blink red beyond the
initial 2 minute period during
power-up.
Indicates: The motherboard is in the
bootloader mode of operation, and is
awaiting a firmware upgrade.
Status LED
Red/green
Power-up
MN-Sx
Sensor
Cold Reset without Power Loss
(commanded from the network
management tool).
• MN-Sx sensor is shut OFF for
2 seconds, and then communication
Cold Reset
No action required.
between the controller and the sensor
is re-established.
Indicates: Normal operation. This
allows the sensor to mimic the “reset
without power loss” scenario.
Status LED
Red/green
• Normal controller function until
download is completed.
Application • LED flashes red briefly following
Download
application download.
• Controller resets.
Indicates: Normal operation.
X
Status LED
Red/green
Firmware
Upgrade
• Flashes ON red for 1 second, then
OFF for 1 second, repeatedly for a
period of 4 to 6 minutes following the
file transfer from the PC to the
controller.
Indicates: Normal operation.
X
Auxiliary
LED
Red/green
Normal
Operation
• Red or green ON, or OFF, as
programmed for the application.
Indicates: Normal operation.
No action required.
No action required.
No action required.
Take action as appropriate
for the application.
MicroNet BACnet Wiring, Networking, and Best Practices Guide
57
Chapter 3
Table–3.1 LED Indications. (Continued)
MNB-1000-15
MNB-1000
MNB-V1, -V2
MNB-300
MNB-70
Controllers &
Remote I/O Module
Indicator
Context
Triac Output
LEDs
Red
Input is
Turned ON
Status
Corrective
Action
Outputs
X
X
X
X
• Solid ON when the respective input is
turned ON.
No action required.
Indicates: Normal operation.
Universal
Normal
Output LEDs
Operation
Red
• Illuminates in proportion to the output
command signal, whether a load is
attached or not.
Indicates: Normal operation.
No action required.
Universal
Normal
Output LEDs
Operation
Red
• Illuminates in proportion to the output
command signal, provided a proper
load is attached to the output.
Indicates: Normal operation.
Note: Output LEDs on open circuit
outputs will not illuminate.
No action required.
Status LED
Red/green
Wait for the upgrade of this
or any other MNB-1000-15
module to occur and/or
Bootloader Mode.
finish. If this state still exists
• Flashes red slowly, beyond the initial several minutes after all
135 seconds, and then indefinitely.
other modules have been
upgraded, do the following:
Indicates: One of the following:
• The MNB-1000-15 remote I/O module 1) Check the wiring
is awaiting a firmware upgrade, or is in connection between the
MNB-1000 and
the middle of a firmware upgrade.
MNB-1000-15.
Note: While the module is being
2) Check the address of the
upgraded, both the XMT and RCV
MNB-1000-15.
LEDs will blink rapidly.
3) Disconnect the
• The firmware is corrupted and the
MNB-1000-15 module from
module can only stay in Bootloader
the remote I/O trunk, reset
mode.
the module, and then
reconnect the module to
the remote I/O trunk.
Remote I/O
X
Power-up
58 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Checkout and Troubleshooting
Table–3.1 LED Indications. (Continued)
MNB-1000-15
MNB-1000
MNB-V1, -V2
MNB-300
MNB-70
Controllers &
Remote I/O Module
Indicator
Status
Corrective
Action
Power-up
• Flashes red slowly for approx.
135 sec., and then becomes steady
ON.
Indicates: The MNB-1000-15 remote
I/O module has not received
communications from an MNB-1000.
1) Check the address
setting at the
MNB-1000-15’s DIP switch.
2) Check the wiring
connection between the
MNB-1000 and the
MNB-1000-15.
3) Once the MNB-1000-15
has been correctly
addressed and connected,
the MNB-1000 will check
the firmware level in the
MNB-1000-15 and upgrade
or downgrade it as
necessary.
Normal
Operation
• Steady green ON as messages are
received from the MNB-1000 and sent
by the MNB-1000-15 remote I/O
module.
No action required.
Indicates: Normal operation. The
module is healthy and is
communicating with the MNB-1000 to
which it is connected.
Configure the
MNB-1000-15, using the
ADI/Remote IO Wizard.
That is, in the application,
connect at least one
remote I/O hardware tag to
control logic.
Wait for completion of the
MNB-1000-15 upgrade
process.
Context
Remote I/O (Continued)
X
X
Status LED
Red/green
X
Status LED
Red/green
Normal
Operation
• Flashes green slowly.
Indicates: MNB-1000-15 remote I/O
module has not been configured in the
application. However, there is ongoing
communication with the MNB-1000.
X
Status LED
Red/green
Normal
Operation
• Flashes green rapidly. XMT LED is
actively flashing.
Indicates: The MNB-1000-15 remote
I/O module is being upgraded.
Normal
Operation
• Flashes green rapidly. XMT LED is not
actively flashing.
Wait for completion of the
Indicates: The I/O modules have
remote I/O module upgrade
been set to an “Offline” state. The
process.
MNB-1000 is upgrading other
MNB-1000-15’s on the bus.
X
F-27360-11
Status LED
Red/green
Status LED
Red/green
MicroNet BACnet Wiring, Networking, and Best Practices Guide
59
Chapter 3
Table–3.1 LED Indications. (Continued)
MNB-1000-15
MNB-1000
MNB-V1, -V2
MNB-300
MNB-70
Controllers &
Remote I/O Module
Indicator
Context
Status
Corrective
Action
Restore communications.
Check: remote I/O module
wiring; remote I/O module
addressing; and the
connection to the
MNB-1000.
Replace the MNB-1000-15
with a compatible unit, or
upgrade its firmware to a
compatible version.
Remote I/O (Continued)
X
Status LED
Red/green
Normal
Operation
• Steady red ON.
Indicates: Normal communications
interrupted between remote I/O
module and the MNB-1000 to which it
is connected. If fallback time has
expired, the module will be in fallback
mode.
X
Status LED
Red/green
Power-up
or Normal
Operation
• Flashes red rapidly.
Indicates: Remote I/O module is
incompatible with MNB-1000 due to
firmware version.
60 MicroNet BACnet Wiring, Networking, and Best Practices Guide
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Checkout and Troubleshooting
Table–3.1 LED Indications. (Continued)
MNB-1000-15
MNB-1000
MNB-V1, -V2
MNB-300
MNB-70
Controllers &
Remote I/O Module
Indicator
Context
Status
Corrective
Action
Communications
X
X
X
X
X
X
X
X
X
X
X
X
F-27360-11
X
X
Transmit
Data LED
Green
Receive
Data LED
Amber
Normal
Operation
• Flashes as messages are sent from
the controller.
Indicates: Normal operation. The
No action required.
controller is healthy and is sending out
a “Poll-for-Master” message.
Normal
Operation
• Flashes as messages are received
from the network.
Indicates: Normal operation.
Note: This LED should remain OFF
after disconnecting the MS/TP
segment from the controller.
Normal
Operation
1. Check for shorted
MS/TP+ to SLD or GND
• Solid ON.
and make corrections as
Indicates:
needed.
1. MS/TP+ shorted to SLD or GND on
2. Verify network wiring
MS/TP network wiring.
integrity, polarity, and
2. Excessively heavy MS/TP traffic.
biasing, and make
corrections as needed.
No action required.
X
Receive
Data LED
Amber
X
Transmit
and Receive
Normal
Data LEDs
Operation
Green and
Amber
• LEDs behave erratically.
Indicates: Improperly biased MS/TP
network segment.
X
Ethernet
10/100 Link Normal
Integrity LED Operation
Green
• Solid ON.
Indicates: Normal operation. The link
No action required.
to the Ethernet PHY (physical layer
transceiver) is good.
X
Ethernet
10/100
Activity
LED
Amber
• Flashes ON for approximately
80 milliseconds each time there is
receive or transmit activity.
Indicates: Normal operation.
Normal
Operation
Ensure that network bias
resistors are installed, and
that EOL resistors are
properly placed on the
network segment daisy
chain.
No action required.
MicroNet BACnet Wiring, Networking, and Best Practices Guide
61
Chapter 3
Service
Components within the MNB-70, MNB-300, MNB-V1, MNB-V2, and
MNB-1000 controllers cannot be field repaired. The MNB-1000-15 remote
I/O module cannot be field-repaired, with exception of the units described in
Field-replaceable Units, below. If there is a problem with a controller or
module, follow the steps below before contacting Schneider Electric Product
Support.
1. Make sure all controllers and modules are connected and communicating
to the desired devices.
2. Check that all sensors and controlled devices are properly connected
and responding correctly.
3. If a controller is operating, make sure the correct application is loaded,
using Work Place Tech Tool (WP Tech). For more information, see the
WorkPlace Tech Tool 4.0 Engineering Guide, F-27254, and the
WorkPlace Tech Tool BACnet Engineering Guide Supplement, F-27356.
4. Record the precise hardware setup, indicating the following:
•
•
•
•
Field-replaceable
Units
Version numbers of applications software.
Controller or module firmware version number.
Information regarding the WP Tech.
A complete description of the difficulties encountered.
There are two field-replaceable parts available for the MNB-1000-15 remote
I/O module:
• MNB-CNTLR-15
• MNB-BASE-15
Module Only
Module Base
62 MicroNet BACnet Wiring, Networking, and Best Practices Guide
F-27360-11
Appendix A
BACnet Best Practices
This appendix provides best practices information for creating and
maintaining a network of MicroNet BACnet controllers and sensors, as well
as a network of MNB-1000-15 remote I/O modules connected to an
MNB-1000 controller. The material presented here is in addition to
information already contained in Chapter 1, Chapter 2, and Chapter 3.
The information in this appendix has been acquired through factory testing
and actual jobsite installations. The topics covered include:
•
•
•
•
•
•
•
•
F-27360-11
I/A Series MicroNet BACnet System Architecture Overview
MS/TP Network Overview
BACnet Rules that Must be Followed
BACnet Best Practice Guidelines
Remote Connectivity
Performance Improvements for MS/TP
Setting Up a Remote I/O Network
Glossary
MicroNet BACnet Wiring, Networking, and Best Practices Guide
63
Appendix A
I/A Series MicroNet BACnet System Architecture Overview
I/A Series Server with
Graphics Web Pages
PC
(Web Browser)
1
Ethernet and/or IP Backbone
PC Workstation
or Laptop with
WorkPlace Tech
Tool Suite
2
4
BACnet MS/TP
RS-485
Optional Serial
Connection
Any
MNB-xxxx
8
Controller
120 ohm
EOL
4
120 ohm
EOL
MNB-1000
AO
1
Data values passed between the
network controller and the server.
2
Data values passed between the
MNB-1000 and the network controller,
using BACnet/IP protocol.
3
Up to 127 MNB-xxxx controllers can be
attached to each trunk of a network
controller, provided there are sufficient
resources available within the device.
Refer to Resource Limits-Additional
Notes, in this section, for more
information related to resource limits.
4
120 ohm
EOL
3
4
120 ohm
EOL
At least one set, and no more than two sets, of
network bias resistors must be present on each
MS/TP network segment, preferably (but not
required to be) in the middle of the segment. The
MNB-300, MNB-1000, and TAC I/A Series Network
Controllers have built-in, jumper-set network bias
resistors for this purpose.
5
One to eight MNB-1000-15 remote I/O modules
may be connected to a remote I/O network.
6
In remote I/O networks, the EOL resistor must be
set at each end of line. The MNB-1000 controller
and the MNB-1000-15 module have a jumper-set
remote I/O EOL resistor for this purpose.
3
BACnet MS/TP
3
120 ohm EOL
Jumper
6
Remote I/O
MNB-1000
Plant
Controller
120 ohm EOL
Jumper
I/A Series Network
Controller
BACnet MS/TP
USB
USB to RS-485
Serial Converter
BACnet Router:
BACnet
Router:
5
MNB-1000-15
Remote I/O
Modules
7
8
120 ohm EOL
Jumper
6
120 ohm
EOL
7
Bias for the remote I/O network is provided by the
permanently enabled, built-in bias resistor on the
MNB-1000 controller. The jumper-set bias resistors
located under the cover of the MNB-1000-15
remote I/O module are set to "disabled" at the
factory, and must not be enabled for this purpose.
8
No other types of devices other than MNB-1000-15
remote I/O modules may be connected to a remote
I/O network, including S-Link sensors,
commissioning and maintenance tools such as the
WorkPlace Tech Tool Suite, etc.
Figure–A.1 Typical System Architecture.
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Resource Limits—Additional Notes
In addition to the resource limits noted in Figure–A.2, be sure to observe the
following:
• Integrating devices other than UNCs, ENCs, or MNB-xxxx controllers
may result in a different maximum number of devices.
• The maximum number of MS/TP devices allowed per MS/TP network is
limited to whichever is smallest among the following: 32 unit loads; the
UNC or ENC resource limit; ENC CPU usage; or the UNC BACnet
shadow object or ENC proxy point limit.
• All MNB-xxxx, UNC-xxx, and ENC-xxx devices use quarter-load
transceivers, which means that an MS/TP network comprised solely of
MNB, UNC, and ENC devices can have no more than 128 total devices
(32 X 4 = 128), consisting of one router plus 127 controllers. Refer to the
definition of Unit Load in the “Glossary ” on page 109.
• A limit of 1500 applies to the UNC BACnet point shadow object and the
ENC proxy points. This limit refers to all BACnet point shadows and
proxy points, regardless of type (MS/TP, BACnet/IP, or
BACnet/Ethernet). Exceeding this limit will result in degraded
performance.
• The UNC-520's resource limit is 600,000 Java Resource Units.
• The ENC-520's resource limit can be determined by comparing the
values for "heap.used" to "heap.max," found in the Resource Manager
view of WorkBench. The value of "heap.used" should never be greater
than 75% of "heap.max." For example, with a "heap.max" of 48MB,
"heap.used" must not exceed 36MB.
Note: ENC-520 Resource Limit
An ENC-520’s resource limit can be calculated based on the “heap.max”
and “heap.used” values, found in the Resource Manager view of
Workbench, as shown in Figure–A.2.
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Appendix A
1
To determine the ENC-520's
resource limit, open the Resource
Manager view, in Workbench.
2
Compare the value for "heap.used"
to "heap.max." The value of
"heap.used" should never be
greater than 75% of "heap.max."
For example, with a "heap.max" of
48MB, "heap.used” must not
exceed 36MB.
Figure–A.2 Finding Resource Limits of ENC-520.
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MS/TP Network Overview
Master-Slave Token
Passing
Devices on an MS/TP network communicate by means of Master-Slave
Token Passing. In a typical MS/TP application, each controller (MNB-70,
MNB-300, MNB-Vx, MNB-1000, UNC, or ENC) on the network is a master
node on that network. As a master node, each device receives the
communication token and then has the opportunity to either send messages,
or make requests, to other devices. In addition, each master controls the
communication token while it is in its possession. See Figure–A.3 for an
MS/TP network diagram.
UNC-520
ENC-520
MNB-1000
Device
Address=0
3
1
EOL
4
2
EOL
2
MNB-xxxx
Controller
MNB-xxxx
Controller
MNB-xxxx
Controller
MNB-xxxx
Controller
MNB-xxxx
Controller
MNB-xxxx
Controller
MNB-xxxx
Controller
Device
Address=4
Device
Address=5
Device
Address=1
Device
Address=3
Device
Address=2
Device
Address=X
Device
Address=6
1
The installing engineer or technician is free to choose the
locations of devices based on job requirements and other
considerations. A device's address or controller type does not
determine or restrict its physical location on a network segment.
For example, if a new device is to be added to an existing
network and it is assigned the next available address, #16, it is
perfectly acceptable to physically connect it to the network
segment between devices #3 and #4, or #8 and #9, etc.
Note: Although the physical locations of devices are not important
from an addressing point of view, be sure to observe note 2
regarding the presence of EOL resistors at each end of line.
2
A 120 ohm ±5% EOL resistor must be installed at
each end of line.
3
Although not required, in most systems the UNC,
ENC, or MNB-1000 is located at the end of line.
4
Additional devices, up to the highest-addressed
device connected to the UNC, ENC, or MNB-1000.
Figure–A.3 MS/TP Network.
With the MaxMaster in all the devices on an MS/TP network set to the
default value of 127, these devices will join the network and then
automatically begin passing the token. Starting with the lowest-addressed
device on the network (MNB-1000, UNC, or ENC), the token is passed to the
next device, and from that device to the next, until it reaches the last device
on the network. A device is determined to be the last one when either no
device with a higher address can be found, or the device’s address equals
the MaxMaster value. The last device then returns the token to the first
device, to begin the cycle anew. This scenario is illlustrated in Figure–A.4,
which shows the token being passed by all the master nodes.
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Appendix A
Note:
• MaxMaster is a property that exists in all MS/TP master devices. This
property tells the device the highest MS/TP address that may exist on
the network. The default value of this property is always 127.
• In an MS/TP network, a device can make requests and send COV
(Change of Value) data only during the time that it has the token.
• When a master device communicates with a slave device, it uses
request/response messaging. That is, the master requests an action,
such as read or write, and then the slave responds with an action
(answer).
MNB-xxxx
Controller
UNC-520
ENC-520
MNB-1000
MNB-xxxx
Controller
Device
Address=0
1
Device
Address=1
MNB-xxxx
Controller
Device
Address=2
MNB-xxxx
Controller
Device
Address=X
Device
Address=3
MNB-xxxx
Controller
Other
Devices
2
Device
Address=4
MNB-xxxx
Controller
Device
Address=7
1
MNB-xxxx
Controller
Device
Address=6
MNB-xxxx
Controller
Device
Address=5
As shown here, the token passing occurs as follows:
a. The token is started by the lowest-addressed
device. Typically this is the router, which is
assigned address 0 (zero).
b. Device 0 makes any requests or responses, and
then passes the token to the next device, Device 1.
c. Device 1 makes any requests or responses,
including the sending of COV data, and then
passes the token to the next device, Device 2.
e. The token is passed in this way until it reaches the
last device on the network, Device X. A device is
determined to be the last one when either no
device with a higher address can be found, or the
device’s address equals the MaxMaster value.
f. Device X, the last device on the network, then
returns the token to the first device, to repeat the
token-passing cycle.
d. Device 2 makes any requests or responses,
including the sending of COV data, and then
passes the token to the next device, Device 3.
2
Additional devices, up to the highest-addressed device
connected to the UNC, ENC, or MNB-1000.
Figure–A.4 MS/TP Network Token Passing.
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Device Addressing
When an MS/TP network is configured, it is recommended that the UNC,
ENC, MNB-1000, or other routing device be assigned the first (lowest)
address on the network, which is 0 (zero). For a UNC or ENC, this is also the
default MS/TP address. As a best practice, other MS/TP devices (MNB-70,
MNB-300, or MNB-Vx) that are added to the network should be addressed
consecutively. In other words, no address numbers should be skipped during
the assigning process. The addressing should be 0 (routing device), 1, 2, 3,
4, and so forth, until the last (highest) address is reached.
BACnet Rules that Must be Followed
Although this appendix mainly focuses on best practices, the items listed in
this section are mandatory and must be followed for any BACnet project.
General BACnet
Rules
No Duplicate Device Instances
Device instances (device ID numbers) must not be duplicated anywhere on
a BACnet network or internetwork. A device is known by its instance, and
cannot be reliably located if it shares that instance with another device.
No Duplicate Object Identifiers within a Device
An object identifier is the combination of an object’s type and its instance
number. No two objects of the same type within a BACnet device may have
the same object identifier.
No Duplicate Network Numbers
Network numbers must not be duplicated anywhere on a BACnet
internetwork. Duplicate network numbers will cause problems with BACnet
routers and may disrupt communications.
Caution: Disruption of communications can affect the entire LAN. If you are
using a shared network, be sure to coordinate with the LAN’s administrator,
so as to minimize the effects of any necessary disruptions.
Devices on a Network Must Share a Single Network
Number
A single site may have multiple BACnet networks, joined by one or more
BACnet routers. While each of these networks must have a unique number,
as stated above in "No Duplicate Network Numbers", each device on the
same network must use the same network number. Generally, only one
BACnet/IP network will exist on a site (or multiple sites connected with
BBMDs). Therefore, all BACnet/IP devices on a site will have the same
network number.
One Communication Path Only
There may be only one communications path between two devices. A
duplicate route (circular path) will cause communications disruptions.
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Appendix A
Caution: Disruption of communications can affect the entire LAN. If you are
using a shared network, be sure to coordinate with the LAN’s administrator,
so as to minimize the effects of any necessary disruptions.
One example of this is caused when two devices, a UNC (or ENC) and an
MNB-1000, are set up to route to the same networks. This commonly occurs
when a BACnet internetwork has a need for both BACnet/IP and
BACnet/Ethernet networks. In this example, assume that the UNC (or ENC)
is configured for both BACnet/IP and BACnet/Ethernet. Then, consider an
MNB-1000 being configured to use BACnet/IP (without disabling
BACnet/Ethernet), to route to the same networks as the UNC (or ENC). At
this point, a circular path is created because both the UNC (or ENC) and the
MNB-1000 will be configured for both BACnet/IP and BACnet/Ethernet. This
occurred because MNB-1000s are configured to use BACnet/Ethernet, by
default. This circular path could have been prevented by disabling
BACnet/Ethernet on the MNB-1000 before activating BACnet/IP.
MS/TP Network
Rules
The following items are mandatory for proper operation of an MS/TP
network.
No Duplicate Addresses
The physical address must not be duplicated on any one MS/TP network. To
avoid this problem, be sure a network wiring diagram is used when
assigning and recording controller addresses.
Caution: Duplicate physical addresses on a single MS/TP network will
disrupt communications on that network.
Note:
• The MS/TP address of an I/A Series MicroNet BACnet controller is set
with its DIP switch.
• A physical address may also be set in a non-physical manner, such as
with the communications configuration of a UNC, ENC, or WorkPlace
Tech Tool (WP Tech).
• Any tool, including WP Tech, WPCT, WorkPlace Flow Balance Tool
(WPFBT) or other, that connects directly to the MS/TP network (not
through a router) must also have a unique address. If your tool appears
to be communicating but will not join the token passing, check for
address conflicts.
Duplicate addresses on an MS/TP network trunk can cause many of the
controllers on the network to stop communicating. The symptoms can
include:
• If two controllers are set to the same physical address, the
communications token will either be lost or be generated twice, thus
causing collisions.
• When two controllers are set to the same physical address, it will appear
that part of the network will be up and part will be down. That is,
controllers will appear online, then offline, for no apparent reason.
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Isolating the Problem
The only method to reliably identify multiple controllers with the same
address is to physically check the DIP switch setting of each controller on
the network. This task can be made easier by temporarily dividing the
MS/TP network into smaller sections, so as to isolate the problem to a
smaller area. In this way, not every device address will need to be verified.
Note:
• The duplicate MS/TP address cannot be determined by which
controllers are online or offline.
• While the WorkPlace Commissioning Tool (WPCT) will sometimes
detect multiple devices with the same address, there is no software tool
that will reliably do so.
Install Terminators
Be sure to install or enable End of Line (EOL) resistors (120 ohm) as
terminators on both ends of the MS/TP network. Failure to do so may result
in intermittent communications. Terminating resistors are important because
they help to reduce signal reflections and RF interference. Ensure that only
two terminators are used, one at each end of the daisy-chained network.
Using more than two terminators can excessively load the network and
disrupt communications.
Make sure that the MNB-300 and MNB-1000 controllers’ EOL jumpers are
set correctly. Having more than the two EOL resistors on an MS/TP network
will cause intermittent communications. EOL resistors are physically set at
the first and last devices (ends of line).
Note: For information on how the EOL jumpers on an MNB-1000 controller
are used in a remote I/O network, refer to “EOL Resistors” on page 107.
Set Bias Resistors
As a requirement of EIA-485 network topology, an MS/TP network must
have at least one set, and no more than two sets, of network bias resistors
on each MS/TP network segment, preferably (but not required to be) in the
middle of the segment. In MS/TP networks, this requires an MNB-300,
MNB-1000, or UNC-520 with the appropriate jumper settings.
Note:
• Jumper-set MS/TP bias resistors are built into UNC-520s.
• For information on how the MNB-1000 provides bias to a remote I/O
network, refer to “Bias Resistors” on page 107.
A network of MNB-Vx controllers without a UNC-520, ENC-520, MNB-300,
or MNB-1000 will not meet this requirement. This may commonly happen
during installation before the router or area controller is installed. In this
situation communications with devices may not be reliable.
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Appendix A
Use Proper Communication Cable
Wiring specifications become much more important as baud rates increase.
In retrofit projects, you must be sure that the existing cable is suitable for
reuse (meets specification). The use of cable that was specified for
NETWORK 8000 ASD or MicroSmart cabling is acceptable if the baud rate
is kept within the range of 9600 or 19.2 k. Upon moving up to a baud rate of
38.4 k or 76.8 k, the cable must meet the approved minimum specification
for I/A Series MS/TP. Most ASD and MicroSmart cable will not meet this
specification and cannot be used at the higher baud rates. Much of the cable
that has been used for previous installations may not meet the specifications
for the higher baud rate.
Be certain that the cable meets, or is lower than, the capacitance
specification for MS/TP, and that it meets the nominal impedance range
specified for MS/TP. See “MicroNet MS/TP Network Wiring” on page 29 for
further information.
Bond the Shield to a Proper Ground
The shield conductor must be bonded to a known, good earth ground to
dissipate any induced signals away from the communication cable. The
shield wire should be continuous from one end to the other, with a bond to
earth ground at only one location. For consistency, this should be done at
the router (MNB-1000, UNC, or ENC). However, it may be done at some
other place, if necessary, for a proper ground. If the bonding is not done at
the router, be sure to document where it is done, for future reference.
Caution: Proper grounding of any EIA-485 shield circuit is important. While
a weak ground may protect communications from low-frequency induced
signals, such as from an AC power line, it is less likely to provide protection
from higher frequency signals, such as radio frequency (RF) radiation.
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BACnet Best Practice Guidelines
Selection of
WP Tech Object
Type for BACnet
A WP Tech BACnet application may contain many BACnet supporting
objects, and many WP Tech object types that represent them. Use care
when selecting the BACnet object type to be used in a WP Tech application.
This section covers the WP Tech object types that directly represent BACnet
supporting objects. You can find a description of these BACnet objects, as
well as the supporting BACnet objects, in the WorkPlace Tech Tool BACnet
Engineering Guide Supplement, F-27356.
Table–A.1 WP Tech Object Types and BACnet Supporting Objects.
BACnet
Supporting
Object Type
AV
Read Only or
Read/Write
(RW)?
Read Only
Analog COV
Client
AV
Analog Setpoint
AV
Read Only
(unless status is
set “offline”)
R/W
WP Tech
Object Type
Analog Monitor
Analog Setpoint AV with priority
array
Prioritya
R/W
Binary Monitor
BV
Read Only
Binary COV
Client
BV
Binary Setpoint
BV
Read Only
(unless status is
set “offline”)
R/W
Binary Setpoint
Prioritya
BV with priority
array
R/W
Command
Priority
AV or BV with
priority array
R/W
Write to RAM or
EEPROM?
n/a
RAM
EEPROM
RAM, EEPROM
(for default only)
n/a
RAM
EEPROM
RAM, EEPROM
(for default only)
RAM
Usage
Used for reading application analog
values.
Used for a peer-to-peer data passing
mechanism between controllers.
Used for writing setpoint data to a
controller. This value is stored in
EEPROM; use normal precautions to
prevent damage to the EEPROM.
Used for writing any data to a controller
that may require the setting of a priority
level. This object requires no precaution
for memory type.
Used for reading application binary
values.
Used for a peer-to-peer data passing
mechanism between controllers.
Used for writing setpoint data to a
controller. This value is stored in
EEPROM; use normal precautions to
prevent damage to the EEPROM.
Used for writing any data to a controller
that may require the setting of a priority
level. This object requires no precaution
for memory type.
Used to add a BACnet priority array to a
BACnet support object.
a.Niagara software cannot write the Relinquish Default value of Analog Setpoint Priority and Binary Setpoint Priority objects.
MS/TP Network
Guidelines
F-27360-11
Keep Exposed Communication Conductors Short
When terminating a communication cable for MS/TP (or any EIA-485
network), do not expose a long length of the conductors. Keep as much of
the conductors covered by the cable shield (the aluminum wrap or wire
mesh) as possible. Excessive exposed length can allow induced
interference.
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Appendix A
Do Not Nick the Insulation When Removing the Cable
Sheath
Most shielded, twisted pair (STP) cables have a small, high-strength cord
between the sheath and the shield foil. This cord is inserted in the cable for
use when tearing the sheath along the length of the cable. A short tear at the
end of the cable allows the sheath to be folded back so that the end of the
sheath can be removed (cut off) without damaging the underlying insulation.
Make Low Resistance Terminations
Ensure that all terminations are low resistance. This can be done by simply:
• Tightening screw terminals.
• Making sure there is no insulation left on the wire where it terminates.
• Avoiding any terminations that are not at a normal place, such as a
controller.
• Carefully ensuring that a tight, low-resistance connection is made, with
very little exposed conductor, whenever a termination must be made
between controllers.
Address Devices Consecutively
Number the MS/TP addresses consecutively. Gaps in addressing add
delays in communications. Addressing should begin with node 0 (zero) and
progress through all nodes, without any gaps, for each separate MS/TP
network. It makes no difference where the device is physically located along
the length of the network. Be certain that you start addressing with 0 (zero)
and end at xx (the highest address), with no gaps in numbering between
them.
A Router’s Address Should Be 0 (Zero)
The physical address of a router (UNC, ENC, or MNB-1000) or area
controller on an MS/TP network should be 0 (zero) on that network.
Although this is not a necessity, it should be followed for consistency, and
because the device with the lowest (active) address will regenerate the
communications token in the event of a lost token.
Few Controllers Per Network
Generally, performance is better with fewer controllers on an MS/TP
network. This is because token passing on MS/TP networks can slow
communications when a large number of controllers are on a single network.
Therefore, it is better to have multiple, smaller MS/TP networks than one
large network.
Use BACnet/IP for the MNB-1000
Whenever possible, it is better to communicate to an MNB-1000 via
BACnet/IP rather than MS/TP. Both BACnet/IP and BACnet/Ethernet are
much faster than MS/TP. In other words, if you are transferring point data
from an MNB-1000 to a UNC or ENC, you should use BACnet/IP whenever
possible.
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Use Higher Baud Rates
Whenever possible, operate at the highest recommended baud rates on the
MS/TP network.
Note:
• Note that the UNC-510-2 has a maximum baud rate of 19.2 k.
• The UNC-520-2, ENC-520-2, MNB-70, MNB-300, MNB-V1, MNB-V2,
and MNB-1000 have a maximum baud rate of 76.8 k.
Use Auto-baud to Change Baud Rate
Do not use the Device Properties dialog box in the WPCT to change the
baud rate of an MNB controller unless you have been instructed to do so, or
you are configuring an MNB-1000 MS/TP network for the first time. Instead,
use the Auto-baud feature in WPCT to change the baud rates of MNB
controllers. For instructions on using this feature, refer to the section on
baud rate synchronization in the WorkPlace Commissioning Tool and Flow
Balance Tool User's Guide, F-27358.
Changing the baud rate manually (outside of the automatic process) will
likely result in controllers that are operating at different baud rates, and as a
result, will not communicate with each other.
Add a Controller as MS/TP Slave After a Failed Upgrade
If an MNB-300, MNB-70, or MNB-Vx controller becomes stuck in boot-loader
because of a failed upgrade, it may be added as an MS/TP slave, which
would then allow you to restart the upgrade. An MNB-series controller that is
stuck in boot-loader mode cannot Auto-baud, and so any communications
will need to be at the same baud rate at which they failed.
Note: If the upgrade failed because of poor communications, be sure to fix
the communications problem(s) first.
Power the Controllers Properly
Be sure that MNB-70, MNB-300, and MNB-Vx controllers, and any
MNB-1000-15 remote I/O modules, have appropriate 24 Vac power. When
power is supplied by a central transformer, be sure that:
• The transformer is appropriately sized for the required VA, with an
adequate margin.
• The length of the power wiring is minimized.
• The appropriate wire size is used, to minimize line drops.
An adequate transformer power margin should be allowed so that
fluctuations in the primary transformer voltage or fluctuations in the
secondary loads do not cause low-voltage power conditions at the 24 Vac
input to the controllers.
The MNB-xxxx series controllers contain circuitry that is designed to protect
the integrity of the embedded flash memory under low-voltage or
questionable input voltage conditions. In the event a controller perceives a
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Appendix A
low-voltage condition, it will set a read-only flag and lock out all writes to
memory, as well as turn off controller outputs. The read-only flag can be
easily viewed in the Device Properties dialog of the WPCT, and will indicate
the controller status as "Operational, Read-Only." The Read-Only status can
help serve as an indicator that the input voltage to the controller may be
questionable.
Note: The MNB-1000-15 remote I/O module also features protection for its
embedded flash memory. When a module detects a low-voltage condition, or
questionable input voltage conditions, it locks out all writes to memory and
turns off its outputs. However, because the remote I/O module is mapped as
an extension of the MNB-1000 controller’s I/O points, not as a separate
device, it does not set a read-only flag. Instead, the WPCT simply shows the
module as offline, and all its inputs will be “NA.”
Attention should also be paid to the wire distance between the central
transformer and the secondary loads, especially in the case of half-wave
input devices like the MNB-Vx, MNB-70, and MNB-300 controllers and
MNB-1000-15 modules. With half-wave type input devices, significant spikes
in the AC input current can occur during the positive half-cycle of the AC
input. Large resistances due to the wire lengths can cause significant
voltage drops at the device’s AC input. In extreme cases, the controller or
module may enter the read-only mode at apparent AC voltages exceeding
20 Vac, due to the asymmetrical nature of the AC input voltage waveforms.
In these cases, reducing the load on the transformer, reducing the wire
length between the controller or module and the transformer, and using wire
rated for higher current will correct the problem.
Repeaters
Existing non-BACnet installations utilizing EIA-485 communications may
contain repeaters. Generally, these will have been required when the
network’s total length is over 4000 ft, or the device count is over 32. Existing
repeaters in a non-BACnet system, such as those used with ASD networks,
will not function with BACnet MS/TP. If you are converting a non-BACnet
system to BACnet, and the network length exceeds 4000 ft, you can do
either of the following:
• Use MS/TP repeaters such as Continuum™ b-Link Repeater
B-LINK-AC-S (RS-485) or B-LINK-F-AC-S (fiber optic)
• Divide the network into multiple, shorter MS/TP networks
If the BACnet system you are creating is part of a UUKL smoke control
system, refer to details related to approved repeaters in the TAC I/A Series
MicroNet BACnet Smoke Control Systems Manual, F-27419.
Set MaxInfoFrames to Value Greater Than 1
MaxInfoFrames is a property of MS/TP master devices. It determines how
many read or write requests, and/or COV notifications, that a device can
make before it must pass the token to the next device.
In a router device (or area controller), MaxInfoFrames should be set to a
value that allows that device to make multiple requests of other devices
before it passes the token to the next device. If the router’s MaxInfoFrames
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is set at 1 (the usual default), the router may not be able to route efficiently to
the MS/TP network. Testing has shown that increasing the value to 5 will
result in a great boost in performance. Refer to Table–A.2 for recommended
MaxInfoFrames values.
Table–A.2 Recommended Values for MaxInfoFrames.
Device
UNC
ENC
MNB-1000 as a router to MS/TP
MNB-1000 as an MS/TP only device
MNB-300 and MNB-Vx
MaxInfoFrames
Value
20
20
20
20
3
Set the MaxMaster Value
MaxMaster is a property of all MS/TP master devices. The default value of
this property is always 127. MaxMaster tells the device what is the highest
MS/TP address that may exist on the network. The following discussion
explains why devices should be addressed consecutively on any MS/TP
network.
Token passing is done by the controller holding the token, which gives it to
the device with the next higher address. In turn, that device gives it to the
device with the next higher address, and so on. When the token reaches the
device with the highest address, that device passes the token back to the
device with the lowest address, which starts the process anew.
A device knows that it is the highest addressed device in one of two ways.
The first way is if its address matches its MaxMaster value. The second way
is when the device cannot find another device with a higher address to which
it can pass the token.
To conserve communications bandwidth on an MS/TP network, a device that
cannot find another device to pass the token to will initially ignore the
missing device(s). However, a missing device cannot be ignored forever, so
after a specified interval of 50 token passes, a poll for master service is
initiated. In this process, the device polls consecutive addresses for the
presence of any devices between its own address and its MaxMaster value.
If no such devices exist, the polling for nonexistent devices can waste a
significant amount of time and data throughput. See the next section,
"Tuning the MaxMaster Property", to improve performance.
Tuning the MaxMaster Property
To overcome some of the performance losses caused by the search for
missing devices, as discussed above in "Set the MaxMaster Value", you
may wish to tune the MaxMaster property. However, keep in mind that this
will be a small performance gain and may not be of benefit unless your
MS/TP network is heavily loaded, with much data passing.
To tune the MaxMaster property, set it to a value that is just one or two
higher than the highest address on the network. Do this for all controllers
except address 0 (zero), which is assigned to the router or area controller. To
be sure that the router or area controller can find any missing devices (for
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example, if part of a network goes down) you must set its MaxMaster value
to 127, which is the maximum number of controllers allowed on a network
(and the maximum valid value for MaxMaster). The reason for setting the
MaxMaster to a value greater than the highest address is to make sure that
one or two unassigned addresses are available for a tool (WP Tech or
WPCT) to join the network. That is, a device, including a tool, cannot join
unless an empty address space is available.
Discussion of Joining Token Passing
Any device that is going to join the token passing of an MS/TP network must
be passed the token before it can pass it on. If there is no activity, then the
device can create a token. This has an impact on adding new devices, even
temporary ones.
Note: A device may initially appear to be inactive when it is added to the
network. This is normal, as it may take several seconds to join the token
passing.
In the discussion of MaxMaster (see page 77), we learned that a device will
periodically look for a missing or new device. The amount of time between
these searches should be about 50 passes of the token. On a well-tuned
and lightly loaded network, this will be quite frequent. On a degraded
network, or one that is heavily loaded with many controllers, the token
passing can be rather slow. How long could it take a new or missing device
to join the token passing? If the time to complete one token pass cycle is
1 second, and the device polls for master service after 50 passes of the
token, the time to join could be anywhere from nearly 0 seconds, to
50 seconds. The length of time depends on how many token passes had
occurred since the last poll for master when the device became active.
The information in this section is provided to help you understand why it can
take a varying amount of time to connect WP Tech, WPCT, or WPFBT to an
MS/TP network, using a serial adapter. If the token passing cycle is slow, it
may take an excessively long time to join the network.
Understanding the Transmit and Receive Data LEDs on
MS/TP Networks
Observation of a device’s transmit data (XMT) and receive data (RCV) LEDs
can be very helpful when troubleshooting certain situations on an MS/TP
network. An understanding of the token passing sequences allows you to
make some reasonable assumptions about how the network is performing.
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Note: (See Figure–3.1 on page 55.)
• The XMT (transmit) LED on a UNC or ENC is amber, and the RCV
(receive) LED is green.
• The XMT LED on all MNB-xxxx series controllers and remote I/O
modules is green, and the RCV LED is amber.
• In EIA-485 (RS-485) communications (such as MS/TP), “TxD” and
“RxD” are traditionally used in reference to transmit and receive.
However, the corresponding common terms, “XMT” and “RCV,” appear
on the labels of some MNB-xxxx devices, and therefore will be used
throughout this document.
In token passing on an MS/TP network, the token is passed from one
controller to the next, in a cyclical manner. The token passing starts with the
lowest-addressed device on the network, which passes the token to the next
device. That device, in turn, passes it on to the next, and so on, until the
token reaches the last device on the network, which then returns the token
to the first device to begin the cycle anew.
Controllers
Because a device only transmits when it passes the token, makes a request,
or responds to a request, it will be in receiving mode almost the entire time.
For this reason, during normal token passing by most control devices, where
there is not a great deal of point polling:
• The RCV LED will appear to be nearly solid ON but will flicker, and every
few seconds it will flash OFF.
• The XMT LED flashes (or flickers) in a fairly consistent pattern,
indicating the following:
– Each time the device receives the token and passes it on, the XMT
LED flashes once.
– Each time that a device receives a request (such as when it is polled
by a UNC or ENC), it will transmit a response and flash the XMT
LED.
• The RCV LED should be ON except when the XMT is ON, or when any
device is performing a poll for master. Poll for master is an MS/TP
means of finding devices that are not communicating.
Router or Area Controller
The normal LED flashing pattern for a router or area controller will basically
be the same as with controllers, described above. However, it is possible
that the device’s XMT LED will flash more frequently because it will be
routing messages or making many requests. This means that, when
compared to a controller, the RCV LED of a router will likely be flickering or
flashing more, instead of appearing to be ON continuously.
Serial Converter
Normal flashing of the LEDs on a serial converter with a tool such as WPCT
may be the same as described above, or the RCV and XMT LEDs may
appear to be flashing about equally. This includes the B&B Electronics
devices recommended for connection to MS/TP networks.
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In General
Generally, MS/TP communications problems are indicated as follows:
XMT LED—Continuous Flashing, RCV LED—No Flashing: Any time the
XMT LED is flashing continuously, without any flashing from the RCV LED,
we know that the device is trying to locate other devices by continuously
polling for master but is receiving no responses. This lack of response is
usually due to a wiring problem, or it may be that the other devices are not at
the same baud rate as the device being monitored.
RCV LED—Continuous Flashing, XMT LED—No Flashing: Any time that
the RCV LED is flashing continuously, without any flashing from the XMT
LED, we know that the device is not transmitting because it is not receiving
the token. The cause is that the device is not receiving packets that it can
understand, which may be due to a wiring problem, interference, or the
wrong baud rate.
RCV LED—Mostly OFF: If the RCV LED is flashing, with or without the
XMT LED, in a pattern where the RCV LED is off a good portion of the time,
a serious wiring issue is present.
BACnet/IP Network
Guidelines
Set the gateway address
If a BACnet/IP device is to communicate with devices that are not on its
subnet, it must have a valid gateway address assigned to it. The gateway is
the IP address of the network interface of the IP router (or switch) that
connects this subnet to the rest of the LAN or WAN. Most UNCs, ENCs, and
MNB-1000s that are enabled for BACnet/IP will need to have a gateway
address. In general, if the network has more than one subnet, a gateway
address will be needed.
Use BBMDs When Needed
BACnet protocol relies heavily on broadcast messages. This reliance on
broadcast messages causes a serious issue for BACnet/IP, as routers and
some switches will not pass broadcast messages. This very simply means
that BACnet/IP broadcast messages will not travel from one subnet to
another subnet. Instead, all BACnet broadcast messages will be stopped at
the gateway to a subnet.
To work past this issue, a device called a BBMD was created that intercepts
BACnet broadcast messages and then forwards them to BBMDs on other
subnets.
Note: Only one BBMD may exist on an IP subnet containing BACnet/IP
devices.
Exception—Foreign Devices: A special case in which a BBMD is not
needed on a subnet is when a temporary device needs to communicate with
a controller, but the device is on a remote subnet without a BBMD. An
example of this is a tool such as the WPCT, which may need to temporarily
communicate with a controller during commissioning. This scenario requires
foreign device registration, which is a method of telling a BBMD that a device
needs to communicate but will be leaving after a given amount of time.
Foreign device registration works well for tools, but it will not work for most
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controllers because most controllers are not designed to work as foreign
devices. In other words, manually entering a controller in a UNC or ENC’s
foreign device table (FDT) will not work.
BACnet/IP Through a NAT Router
BACnet/IP communications through a Network Address Translation (NAT)
router will fail unless special provisions are made in the LAN’s firewall/NAT
router. The reason for this is that a BACnet message contains the source
address, which is the address of the device that sent the message. This
source address is used by the destination device to send any responses
back to the source. The NAT will cause that source address to be incorrect
because of the address translation.
BACnet Ethernet
Network Guidelines
BACnet/Ethernet is Not Routed
Ethernet messages are not routed through IP routers. This implies that
BACnet/Ethernet should be used only on a single subnet. If BACnet
messages must be sent from one subnet to another, consider using
BACnet/IP with BBMDs, instead. See “Use BBMDs When Needed” on page
80.
An Exception: There is one exception to this. If the subnetting is
accomplished using a managed switch, instead of a router, the switch may
be configured to pass Ethernet messages. This could be a method used for
spanning subnets with BACnet/Ethernet. However, the use of this method
could cause problems if both BACnet/Ethernet and BACnet/IP are used on
the same LAN. Plan carefully! Keep in mind that if this is a shared network,
you will not have control of the switch or router, and may lose certain
capabilities at anytime.
Do Not Leave BACnet/Ethernet Enabled if Not Used
When an MNB-1000 is configured as an MS/TP-only device, and does not
use BACnet/IP or BACnet/Ethernet, you must be sure that BACnet/IP and
BACnet/Ethernet are both disabled. Leaving BACnet/IP or BACnet/Ethernet
enabled would mean that the MNB-1000 is still a router. This can create
conditions under which the network is flooded with “Who is router to
network” and “I am router to network” messages.
If a secondary means of accessing the MNB-1000 is needed, and you must
have access through the Ethernet interface, it will be necessary to disable
BACnet/Ethernet and enable BACnet/IP for each MNB-1000. In addition,
each MNB-1000 will need to be on a separate BACnet/IP network, each with
a separate UDP port.
BACnet Guidelines
for UNCs and ENCs
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Fewer Points Equals Better Performance
When using a UNC or ENC to communicate to a BACnet MS/TP network, it
is important to recognize that minimizing traffic on the network is the best
way to achieving optimum performance. The number of active polled points
significantly affects traffic on a BACnet MS/TP network, and thus its
throughput. The more traffic there is, the more significant its impact on
performance.
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In addition, there are limits to the number of objects a UNC or ENC can
support. It is recommended that the device be limited to a total of 1500 point
shadow objects (UNC) or proxy points (ENC). This quantity may be less,
depending on the available resource count in the UNC or ENC.
While the total number of points can safely be 1500, the number of points
that are polled at any given time should be fewer, for better performance. To
limit this number, use PollOnDemand containers. See the following section.
Use Poll On Demand for Schedules, Alarms, and Trends
UNCs—Use PollOnDemand Containers
UNCs place all BACnet objects, when learned, into “poll always” containers.
All objects other than those that need to be frequently updated (schedules,
alarms, trended objects, etc.) should be moved to PollOnDemand containers
to minimize network traffic.
Note: Keep in mind that all containers that are not PollOnDemand
containers are PollAlways containers, which will poll for values on a
continuous basis.
ENCs—Do Not Add Point Extensions Unless Necessary
In ENCs, proxy points function in a "poll on demand" manner when learned.
However, when point extensions (alarm, history, or both) are added to a
proxy point, the extension will cause the point to poll often. As a best
practice, use proxy extensions only when necessary.
Delete Unused Points
Any BACnet objects that are learned in the UNC or ENC, but are not
needed, should be deleted. Generally, all objects are learned during learning
of a BACnet controller, and those not needed for control or GxPages should
be deleted.
One method of doing this is:
1. Perform the learn of BACnet points.
2. Create a PollOnDemand container.
3. Give this container a name, such as “Holding” or “Store,” that will signify
that it is used for storing shadow objects.
4. Move all of the point shadow objects into this container.
5. Do not link to any of the points in this container. Using this PollOnDemand
container to store BACnet objects will prevent unnecessary polling of
values.
6. Create a second PollOnDemand container. Use this container for
developing your graphics.
Note: PollOnDemand containers are usefull only with GxPages,
because the point values are updated only when the GxPage is active.
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7. Transfer the point shadow objects to the appropriate container as
needed, noting that:
• Points for graphics go into a PollOnDemand container.
• Points that need to update continuously go into other containers.
8. Once the database is complete, simply delete the original PollOnDemand
container named Holding or Store, if desired, and you will have cleaned
up any unused points.
Keep the UNC or ENC Routing
A UNC or ENC will not tolerate networking configuration errors. If a UNC or
ENC detects a duplicate route (a circular path), it will stop routing BACnet
messages. When this happens, the station must be restarted to begin
routing again. If the network error that caused routing to stop still exists, then
routing will stop again, and the error must be investigated and corrected.
The behavior of the BACnet router can be changed in the ENC to keep
routing enabled, by changing the property, [station]\Drivers\BacnetNetwork\
BacnetComm\Network\MaintainRoutingEnabled, to a value of True.
However, the error that originally caused the routing to stop must be
investigated and corrected.
The behavior of the BACnet router in a UNC with a BACnet module (jar file)
of build bacnet-2.305.515a or later can be changed to keep routing enabled.
Instructions for this may be found in the release notes for build r2.301.522.
Keep the Processor Idle Time Above 20%
At no time should the processor idle time be less than 20%. Allowing
processor idle time to drop below 20% may have undesirable effects,
including the loss of control functionality. A low idle time is certain to
adversely affect communications of any type, including BACnet.
The most common cause of low processor idle time is an excessive number
of program objects. As a general guideline, keep the number of program
objects fewer than 100. Less is better. If program objects must be used, one
way of reducing the quantity is to combine the functions of two or more
program objects into one.
UNC and ENC Bias Resistors
Always keep in mind that each MS/TP network should have at least one set,
but no more than two sets, of bias resistors. When using a UNC-520 or
ENC-520, or one or more MNB-1000s, determine which device(s) will
provide the bias resistors for the network and set the jumpers appropriately.
Use COV Subscription for Slowly Changing Points
The use of COV subscription at the UNC or ENC level has the potential to
increase performance. Use COV for points that do not change value quickly.
The frequency of updates can be controlled with the covIncrement property.
Setting the COV increment to a larger value lessens the update frequency,
thus potentially improving performance.
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Do Not Use COV for Priority Type Points
The UNC or ENC uses a “rewrite mechanism” to detect whether a point is at
the value that the UNC or ENC last commanded. Priority type points stay in
the poll queue even when they are COV subscribed. Due to this rewrite
mechanism, priority points have the potential to increase update times in the
UNC or ENC. The priority type points are: all outputs, analog value priority
points, and binary value priority points. These points should be avoided for
COV subscription.
Tuning Policy for ENC
Refer to the section, “About Tuning Policies,” in the Niagara AX-3.x User
Guide for a discussion of tuning policies and recommendations that can be
used to optimize the way write requests (to writable proxy points) and read
requests are evaulated in ENCs.
General BACnet
Guidelines
Consider Network Design Carefully
When designing BACnet networks and internetworks, keep the end result of
a functioning system in mind. A simple MS/TP network is straight forward to
design and install, but the complexity increases dramatically when networks
are joined together to form an internetwork. Proper planning and
understanding of modern networking principles is desirable for creating a
BACnet internetwork that includes IP and Ethernet routing and switching.
If a shared network is included in the design, close coordination with the
facility’s IT department may be required. Making prior assumptions about an
IT department’s capabilities, or their ability to cooperate, may be
undesirable. Having your own staff trained in networking essentials will help
considerably in working and communicating with the appropriate IT
personnel.
Remote Connectivity
Remote connectivity is the need to access a BACnet device that exists on a
network (or subnet) other than the one on which your tool’s PC resides. To
accomplish remote access communications, we need to consider the
following items.
Item One. Remote access requires a connection using a
telecommunications interface, which can be a telephone line or a broadband
Internet connection. The BACnet datalink layer type that can utilize these
types of connections is BACnet/IP. This generally excludes all other BACnet
connections.
Item Two. BACnet relies heavily on broadcast messages. Broadcast
messages are generally not passed through IP routers, so special provisions
must be made to transfer BACnet broadcasts from one network subnet to
another. A special BACnet/IP device, called a BACnet Broadcast
Management Device (BBMD), was created for the purpose of transferring
broadcast messages from one subnet to another. The BBMD does this by
transforming any BACnet broadcast messages (BACnet/IP,
BACnet/Ethernet, or MS/TP) that it receives into unicast BACnet/IP
messages that are directed to the other BBMDs on the BACnet internetwork.
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Item Three. BACnet/IP messages are not compatible with Network Address
Translation (NAT). This means that if NAT is used (check with the IT
department), it must be bypassed by some means.
Considering the above three items, we will use BACnet/IP for remote
connectivity and make special provisions for its use.
Items necessary for BACnet/IP communications are:
•
•
•
•
IP address
Subnet mask
UDP port number
Unique but common network number
Additional items for BACnet/IP communications between subnets are:
• Gateway address
• One BBMD is needed, per subnet, with appropriate BDT entries
Additional items that may be required for off-site access are:
• Open the BACnet/IP UDP port on the firewall
• Configure a one-to-one NAT
Note:
• Any BACnet/IP communication that passes through a firewall may
require changes to the firewall settings. Make certain that the BACnet/IP
UDP port is open. This includes any personal firewall software on a PC.
• The UDP port default is 47808 (0xBAC0). The UDP port only needs to
be changed if there is a network conflict. In other words, if IT personnel
have instructed you to change it. Secondly, you may change the port if
there is a need for two (or more) separate BACnet/IP networks on the
same physical network media. In that case, each of these BACnet/IP
networks would then be assigned separate network numbers, with each
network using a separate UDP port.
BBMDs–
Connecting
BACnet/IP Devices
on Different
Subnets
Each BBMD must hold the addresses of all other BBMDs that it will work
with, in a table called the BACnet Distribution Table (BDT). When a BBMD
receives a BACnet broadcast message (either a request or a response), it
sends the message as a Forwarded-NPDU message to all other BBMDs in
the BDT. When a BBMD receives a Forwarded-NPDU message from
another BBMD, it broadcasts the message on its local networks (BACnet/IP,
BACnet/Ethernet and MS/TP). Through these actions, the broadcast
messages will be sent to all BACnet devices on the internetwork. See
Figure–A.5.
Secondly, BBMDs hold all addresses of temporary BACnet devices, such as
a PC with WPCT, in a table called the Foreign Device Table (FDT). A foreign
device is a BACnet/IP device with the capability of self-registering with a
BBMD, to allow the BBMD to transfer broadcast messages to and from that
foreign device. The foreign device registration is timed to expire
automatically. To continue communicating, the foreign device must
re-register shortly before the time expires. Foreign device registration can be
used for permanent devices, in case a BBMD is not available on the local
subnet. However, the device must have the built-in capability of being a
foreign device and must also be configured as such.
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In an IP network, each subnet that is to be part of the BACnet internetwork
should have a BBMD. It is likewise important that only one BBMD exist per
subnet, for a single BACnet/IP network. Having multiple BBMDs on the
same subnet will flood the subnet with unnecessary IP traffic and greatly
slow BACnet communications.
IP Router
10.1.137.200
10.1.142.200
10.1.144.200
Segregates the network into
subnets. Each interface of
the router becomes the
gateway (GW) to a subnet.
Subnet 10.1.137.0
BBMD
BACnet/IP
Device
BACnet/IP
Device
IP =
10.1.137.6
Mask = 255.255.255.0
GW =
10.1.137.200
IP =
10.1.137.43
Mask = 255.255.255.0
GW =
10.1.137.200
IP =
10.1.137.17
Mask = 255.255.255.0
GW =
10.1.137.200
Subnet 10.1.142.0
BBMD
BACnet/IP
Device
BACnet/IP
Device
IP =
10.1.142.47
Mask = 255.255.255.0
GW =
10.1.142.200
IP =
10.1.142.38
Mask = 255.255.255.0
GW =
10.1.142.200
IP =
10.1.142.66
Mask = 255.255.255.0
GW =
10.1.142.200
Subnet 10.1.144.0
Foreign Device
(Example: PC Workstation
or Laptop with WorkPlace
Tech Tool Suite)
IP =
10.1.144.91
Mask = 255.255.255.0
GW =
10.1.144.200
Figure–A.5 Subnetted LAN with BACnet/IP.
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Setup of BBMD in
the MNB-1000
The use of BBMD in the MNB-1000 requires firmware revision 1.3 or later,
and WPCT 1.4 (WP Tech 5.3) or later. Setup is done in the Device
Properties dialog for the MNB-1000 device, using the IP and BBMD tabs.
Examples of these properties are shown in Figure–A.6 and Figure–A.7.
Figure–A.6 MNB-1000 Device Properties Dialog—IP Tab.
All properties on the IP tab of the MNB-1000 Device Properties dialog must
be entered, including:
• Enable IP Port—Check box must be selected.
• Network Number—Must be unique per internetwork. This means that all
BACnet/IP devices that will share data with each other must have the
same network number.
• IP Address—Must be a static address or a reserved DHCP address.
• IP Subnet Mask—Enter the assigned IP address for the subnet mask.
• Default Gateway—Must be included. This is the address of the router
interface.
• UDP Port—The default is 47808 (0xBAC0).
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• Device Type—Choose an option from the pull-down menu:
– Standard IP Device—Select to set up device to act as standard
BACnet IP device.
– BBMD Device—Select to enable device’s BBMD functionality.
– Foreign Device—Select to set up device as a foreign device.
Figure–A.7 MNB-1000 Device Properties Dialog—BBMD Tab.
On the BBMD tab, enter the IP address, UDP port number, and distribution
mask for every other BBMD that exists on this BACnet internetwork.
Recalling that the UDP port for all BACnet/IP devices must be the same, set
the port the same here as on the IP tab. The distribution mask determines
how the broadcast messages are sent between subnets. Most LANs will use
two-hop distribution, which should always work, whereas one-hop
distribution will only work if the LAN is configured for it. Always leave the
distribution mask at “255.255.255.255” (FF:FF:FF:FF) unless the LAN has
been configured for one-hop distribution. If the network is set for one-hop
distribution, you must request the distribution mask from IT personnel.
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Use of VPN for
Off-site Access
Use of a Virtual Private Network (VPN) for off-site access is a means of
bypassing the NAT router (Figure–A.8). A VPN connection set up for
remotely joining a LAN will make certain that both the tool’s PC and the
devices being accessed have addresses on the same LAN. This means that
NAT will not be involved, and will not be an issue. Many types of VPN are
available, and many different configurations and capabilities exist. To make
this access possible, you will need a client/server VPN meant for remote
access to a network.
When using a VPN, you will need to configure the tool to register as a
foreign device to a BBMD. In WP Tech or WPCT, this is done automatically
when you select Connect to Remote Internetwork. The connection to a
BBMD is required because a VPN connection will not pass broadcast
messages. This means that for off-site access, at least one BBMD is
required.
NAT Router,
Firewall, etc.
Internet
NAT Router,
Firewall, etc.
LAN - Subnet 10.9.8.0
LAN - Subnet 172.1.0.0
Foreign Device
(Example: PC Workstation
or Laptop with WorkPlace
Tech Tool Suite)
VPN Client
172.1.0.x
1
VPN Server
BBMD
IP = 172.1.0.5
1
VPN client software will create a tunnel connection to
the VPN server, join the remote LAN, and be issued
an IP address (172.1.0.x) on that LAN.
Figure–A.8 VPN Used for Off-site Access.
When using a VPN, the firewall must be set up to open the BACnet/IP UDP
port. In most cases, the VPN will be a part of, or be behind, the firewall and
will be constrained by firewall rules.
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Appendix A
Using a BBMD with
an NAT Router
In some cases where remote access is required, a BBMD may be used as
an NAT router (Figure–A.9). Because this is a more complicated method to
set up and use than a VPN, its use is suggested only for projects where a
VPN is not a possibility. This approach requires in-depth networking
knowledge. In the case of a shared LAN, the facility’s IT department will
need to perform the setup.
When using BACnet/IP through an NAT router, it is necessary to use a
“one-to-one” NAT. This is an NAT setup in which the IP device has the same
actual and apparent IP addresses. The effect is the same as the device
having a “public” IP address. This would need to be done for BBMDs and
foreign devices (tool PC) alike.
IP Router
One-to-one NAT Port 47808
open
Each interface of the router
becomes the gateway (GW)
to a subnet.
10.1.137.200
1
Subnet 10.1.137.0
BBMD
BDT
BACnet/IP
Device
BACnet/IP
Device
IP =
10.1.137.6
Mask = 255.255.255.0
GW =
10.1.137.200
10.1.137.6
197.196.1.66
10.1.144.4
IP =
10.1.137.43
Mask = 255.255.255.0
GW =
10.1.137.200
IP =
10.1.137.17
Mask = 255.255.255.0
GW =
10.1.137.200
10.1.142.200
Internet
NAT Router, Firewall, etc.
10.1.144.200
Apparent IP
197.196.1.66
Subnet 10.1.144.0
1
2
BACnet/IP
Device
BACnet/IP
Device
BBMD
IP =
10.1.144.47
Mask = 255.255.255.0
GW =
10.1.144.200
IP =
10.1.144.48
Mask = 255.255.255.0
GW =
10.1.144.200
IP =
10.1.144.4
Mask = 255.255.255.0
GW =
10.1.144.200
One-to-one NAT. Note that the actual
and apparent IP addresses of this BBMD
device (197.196.1.66) are the same,
therefore there is no address translation
problem. Only one BBMD will be set up
with one-to-one NAT.
The BBMD on subnet 10.1.144.0 has an
actual IP address that is not compatible
with the 10.1.142.0 subnet (or any of the
others). Static routing must be built for
this LAN to allow the BBMD with
address 197.196.1.66 to communicate
with the devices on all subnets.
BDT
2
10.1.137.6
197.196.1.66
10.1.144.4
Subnet 10.1.142.0
BACnet/IP
Device
BBMD
BDT
IP =
10.1.142.7
Mask = 255.255.255.0
GW =
10.1.142.200
IP =
197.196.1.66
Mask = 255.255.255.0
GW =
10.1.137.200
1
10.1.137.6
197.196.1.66
10.1.144.4
Figure–A.9 LAN Diagram with One-to-One NAT.
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WP Tech/WPCT
BACnet/IP Remote
Connection Setup
A local connection with BACnet/IP refers to communication between two or
more BACnet/IP devices that are on the same IP subnet. Remote
connectivity refers to communication between two or more devices that are
on different subnets of the same, or different, networks.
If BACnet/IP was previously selected in WP Tech or WPCT, the
communication settings for BACnet/IP will be displayed at the tool’s startup:
an active local IP address, the subnet mask, and a UDP port number (if
other than the default port, 47808).
Figure–A.10 BACnet/IP Local Connection.
In the example shown in Figure–A.10, the workstation is located on subnet
10.1.142.0 and is acting as a local BACnet/IP device (Local IP Address:
10.1.142.84). The default UDP port number (47808) is used, and so it is not
illustrated. BACnet messages will be sent on the local subnet, and any
BACnet/IP devices on this subnet that are also using the same UDP port
number (47808) will communicate with the WP Tech or WPCT.
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Figure–A.11 BACnet/IP Remote Connection.
In the example shown in Figure–A.11, the workstation is located on subnet
10.1.142.0 (at IP address 10.1.142.84), but it is communicating with a BBMD
on a different subnet, 10.1.137.0 (at IP address 10.1.137.6). With this setup,
all broadcast BACnet communications will be directed to the BBMD and
processed by the BBMD as required by its router table, broadcast
distribution table (BDT), and foreign device table (FDT) entries. The BBMD
will direct any responses that it receives, back to the WP Tech or WPCT.
Note: With a remote connection, any devices that are on the local subnet
will not appear in the WP Tech or WPCT. In Figure–A.11, above, the
BACnet/IP devices located on the 10.1.142.0 subnet will not be shown on
the list. Only devices having their communications directed through the
BBMD will be shown.
WP Tech or WPCT will automatically register as a foreign device to a BBMD
when Access a remote internetwork is chosen for the connection type, as
shown in Figure–A.12.
A networked PC may have multiple IP addresses. This might be the result of
having multiple network interfaces (i.e. wired Ethernet and WI-FI wireless) or
multiple services that provide IP addresses (i.e. company LAN and VPN
network). The possibility of multiple IP addresses necessitates the ability to
choose which IP address the WP Tech or WPCT will use. As shown in
Figure–A.12, this can be changed in the BACnet Communications
Settings-IP Protocol dialog box.
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The Local IP Address and Subnet Mask field will list all available IP
addresses, allowing any of them to be chosen from the drop-down list for
BACnet/IP communication. It is necessary to select the correct IP address to
open communication between the tool and the devices you wish to
communicate with. This selection identifies the local BACnet/IP address that
will be used, and therefore also selects the specific interface associated with
that address.
Figure–A.12 WP Commissioning Tool BACnet/IP Connection Setup.
In addition to setting the IP address that will be used, BACnet/IP requires
you to specify a UDP port. The default port for BACnet/IP is 47808
(0xBAC0). If the port of the network that you are connecting to has not been
changed, this default value (47808) may be entered by simply leaving the
UDP port field empty.
To connect to a local network, select Access a local internetwork. To
connect to a remote network, select Access a remote internetwork and
then enter the IP address of the BBMD that will provide the interface to the
remote network.
When you are satisfied that the correct settings have been made, click
Finish to save these settings, and then click OK to begin browsing the
network for devices.
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Appendix A
Performance Improvements for MS/TP
The MNB-70, MNB-300 and MNB-Vx firmware release 1.4 and later enables
significant performance improvements for MS/TP network speed when
implemented properly. This section covers implementation and optimization
of these performance improvements.
Note: The use of COV subscription requires full token passing.
Implementing
Performance
Improvements
The performance improvement gained with MNB-xxxx firmware 1.4 and later
comes from two sources. First, it comes from an improvement in the
efficiency of the controller communications on the MS/TP network. The
second source is the availability of change of value (COV) subscription in
the controllers, which provides a significant opportunity to enhance
performance.
To increase the efficiency of MS/TP communications, simply install the 1.4x
firmware in all MNB-xxxx devices. If your MS/TP network uses an
MNB-1000 as a router, you must upgrade this controller to version 1.41 or
later before upgrading the MNB-300 and MNB-Vx controllers. This is done to
ensure that the MNB-1000 router is capable of handling the increased traffic
capabilities (higher throughput) on the enhanced MS/TP network.
Note: The MNB-70 comes pre-installed with firmware version 1.41.
After installing the 1.4 firmware in all MNB-300 and MNB-Vx controllers, you
should expect an observable MS/TP performance improvement. You will see
this through decreased data update times. Keep in mind, however, that the
amount of improvement depends on many factors, primarily the number of
data points, the number of devices, and the baud rate.
The implementation of COV subscription in the MNB-70, MNB-300,
MNB-1000 and MNB-Vx with the 1.4x firmware allows the controller to
function as both a COV server and a COV client. This allows a form of
peer-to-peer communications between the MNB-xxxx controllers. The
peer-to-peer links are created with Link Builder, which is part of the WPCT.
Refer to the WorkPlace Commissioning Tool and Flow Balance Tool User's
Guide, F-27358, for detailed instructions on the use of Link Builder.
Note: UNCs support COV as a client only. This means that COV will
function to transfer data from controller devices to the UNC, but not from the
UNC to a controller.
The performance gain with COV subscription comes primarily from
decreasing the number of messages needed to transfer data from one
device to another. This is done by decreasing the number of request and
response (polling) messages, replacing these messages with a “push” of the
data whenever the value changes beyond a threshold (the COV increment
value). By not requiring request messages, almost one half of the messages
for a point are eliminated. In addition, the data is sent only as needed, when
it changes, instead of during every poll cycle.
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COV Subscription in a UNC
To implement COV subscription in a UNC, two useCOV properties must
have their values set to True, first in the device, and then in the point.
BACnet Device Shadow Object
The first place where the useCOV property must be set to True when
implementing COV subscription, is in each BACnet device shadow object
(Figure–A.13). The useCOV property tells the UNC station’s BACnet service
whether the device is capable of being a COV server (the UNC is always a
client). If the value of useCOV is True, then COV subscription is enabled for
that device. If the value is False, then COV subscription is disabled. The
useCOV value for device objects is acquired when the device is learned, and
therefore takes its value from the controller. If the device was learned prior to
the upgrade to firmware revision 1.3 (MNB-300 and MNB-Vx) or 1.4
(MNB-1000), the useCOV property will be False. The useCOV value may
also be changed to enable (only if the device supports it) or disable COV
subscription for a device, as needed.
Note: COV subscription is only supported in MNB-300 and MNB-Vx
firmware revisions 1.3 and later, and in MNB-1000 firmware revisions 1.4
and later.
Figure–A.13 BACnet Device Shadow Property Sheet Showing the useCOV Property.
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BACnet Point Shadow Object
The second place where the useCOV property must be set to True, when
implementing COV, is in the BACnet point shadow object (Figure–A.14).
Here, the useCOV property determines whether the BACnet service will use
the request/response method for polling values, or the COV subscription
method. The value of useCOV must be set to True to allow subscriptions.
Figure–A.14 BACnet Point Shadow Property Sheet Showing the useCOV Property.
The useCOV property for point shadow objects has a default value of False.
Learning a device’s points will result in the useCOV property of the points
being False. The point’s useCOV property must be manually changed to
True to allow the UNC to subscribe to that point.
Changing the useCOV property of either a device or point object may be
done manually, one at a time, or you can use the AdminTool object to
change the useCOV property of all objects at the same time. The AdminTool
object was created to provide a means for searching and replacing
properties in a running UNC station. The AdminTool object is described in
Chapter 6 of the Niagara Standard Programming Reference Manual, where
full instructions on its use are provided. Refer to “Using AdminTool Object to
Change useCOV Value” on page 98 for simple instructions on using the
AdminTool object for this purpose.
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COV Subscription in an ENC
The ENC uses COV subscription, which is available if the device supports it.
A property named UseCov in the ENC’s proxy object is the equivalent of
useCOV in the UNC’s device object. To enable COV subscription, the
UseCov property is set to true, in Workbench (Figure–A.15). Note that an
ENC can be a client or a server, unlike a UNC, which is always a client.
Note:
• COV subscription is only supported in MNB-300 and MNB-Vx firmware
revisions 1.3 and later, and in MNB-1000 firmware revisions 1.4 and
later.
• When configuring the ENC as a COV server, additional setup is required
to enable this functionality.
Figure–A.15 BACnet Device Object Proxy Property Sheet Showing the useCOV Property.
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Appendix A
Using AdminTool
Object to Change
useCOV Value
This section describes an example of how the AdminTool object can be used
to change the useCOV value.
Caution: The AdminTool object is a simple, yet very powerful tool. Most
properties of objects within a UNC station can be modified with the
AdminTool object. However, because the AdminTool object does not ask you
to confirm before proceeding with a search and replace operation, it must be
used with caution. Not doing so can have serious, detrimental effects.
Therefore, it is highly recommended, and this is considered a best practice,
that you save a proper backup of the station before beginning any search
and replace.
Preparation for Use
For our example, we will copy the AdminTool object from the local library
(…/tridium/apps/AdminTool—see Figure–A.16) and paste it into a container
in the UNC station. Rename the AdminTool object as you like, perhaps
“useCOVtrue” or similar.
Figure–A.16 Path to AdminTool Object.
After pasting the AdminTool object into a container of the UNC station, we
must set four properties on the Config tab of the AdminTool object property
sheet, to enable the search and replace function (Figure–A.17). These four
properties are:
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rootNode: The top level in the station at which you want the AdminTool
object to work. This will probably be BACnetTemp or the container in which
you have stored the device shadow objects.
propertyName: The name should be “useCOV” for all BACnet device and
point shadow objects.
newValue: The value should be set to True to enable (use COV
subscription), or False to disable.
recurseChildren: Setting the value to True allows search and replace in
the root node (container) and all of its child/grandchild nodes, while setting
the value to False means the AdminTool object will search and replace in
the root node container only.
Unused and optional properties of the AdminTool object are:
elementName: Does not apply to the useCOV property, and therefore must
be kept blank (a dash, “-”) to work.
objectTypeFilter: Optional.
nodeNameFilter: Optional.
propertyValueFilter: Not used for the useCOV property (an asterisk, “ * “).
The two optional properties, above, may be used if you have a need for only
certain BACnet objects to be COV subscribed. You may filter the search and
replace by the type of object (objectTypeFilter), part of the object name
(nodeNameFilter), or both. This would allow you to set only certain objects to
be COV subscribed, and may be helpful in allowing some point objects to
communicate by request/response only.
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Figure–A.17 AdminTool Object Properties.
Performing a Search and Replace
The search and replace can be initiated by choosing SearchAndReplace in
the Commands menu, or by right-clicking on the AdminTool object and then
selecting SearchAndReplace.
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Optimizing the
covIncrement Value
To get the most benefit from COV subscription, and to ensure that the
network performs well, COV must be understood and implemented correctly.
COV Subscription Process
First, consider what happens during a COV subscription. The steps involved
in a single COV subscription are as follows:
1. The COV client (UNC or ENC) makes a request to the COV server
(controller) for the subscription to a single point. Included with the request
is a time value for how long the subscription should last
(covResubscriptionInterval). The default value for
covResubscriptionInterval in a UNC or ENC is “900” (seconds, or
15 min.). In an MNB-xxxx controller, the default value of
covResubscriptionInterval is “300” (seconds, or 5 min.).
2. If the subscription is successful, the COV server will respond back to the
client.
3. Anytime the value of the subscribed point changes more than the
covIncrement amount, the COV server will send the present value and
status to the COV client.
4. Within the covResubscriptionInterval time, the client must resubscribe, in
order for the subscription to continue. This should occur about
30 seconds prior to the expiration time.
covIncrement Value too Small
Next, imagine what will happen if the covIncrement value is too small, or
even zero. If the covIncrement is a very low value, then every time that the
value changes even slightly, the controller will attempt to send the
subscription to the COV client(s). If a controller has a large number of points,
and it is attempting to send them too often, or if a large number of controllers
are sending data too often, it is possible to slow the traffic on the MS/TP
network. This creates a situation where using COV subscription can actually
be slower than using data poll that is strictly request/response. For an
example, take a point that is used for mixed air temperature, degrees C.
Suppose this point has a covIncrement set to “.001.” Then, every time that
the value would change just 1/1000 of a degree, the COV increment would
be satisfied and the COV server would send the present value to the client.
This point would update very frequently, thus flooding the network.
covIncrement Value too Large
Conversely, if a point’s covIncrement value is too large for a specific use, the
point value will not reach the COV increment as often as necessary to
ensure current values. For example, take a point with data for a supply air
static pressure, in inches of water column, set to a covIncrement of “1.0.”
Because the pressure data would be updated only when there are large
fluctuations in pressure (1.0 in. WC or larger), or at the resubscription time
(determined by covResubscriptionInterval), both of which are infrequent, the
result is that static pressure data at the UNC or ENC will not be very current.
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Choose the Right covIncrement Value
It is important that each point has an appropriate covIncrement value, to
ensure that the data is updated often enough to be current but not so often
that it will cause the network to be flooded with unnecessary traffic. Default
covIncrement values have been implemented in WP Tech for various
BACnet point types and usages. These default values have been chosen to
be appropriate for most uses.
It is important, however, to make certain that each point has a covIncrement
value that matches its usage. For example, a point used for temperatures
(with units in °F or °C) would need a very different covIncrement than a point
used for static pressure (with units in InWC). In WP Tech, the default value
for a given point is used whenever the value for COV Increment is “NA”. This
value may be changed at the application level by entering a valid value in
the COV Increment field.
The COV increment may also be changed by any BACnet tool that is
capable of changing point properties. The UNC or ENC point shadow
objects support covIncrement only in the full version of the BACnet shadow
object. Any BACnet shadow object that was learned as a “lite” object will not
allow reading of covIncrement.
Note: A “full” version of a BACnet shadow object shows all its properties,
while a “lite” version only shows properties that are commonly used.
In addition to verifying an appropriate value for covIncrement, you should be
aware that points that need to be written frequently, such as any points that
are being controlled by the UNC or ENC, or points such as schedules,
should be set so that they do not use COV (i.e. useCOV = False). This will
help the station perform as efficiently as possible. Conversely, points that are
not written often, or are written only as manual operation (override), are
good candidates for COV subscription.
The UNC and ENC use a “rewrite mechanism” to ensure that the UNC or
ENC is the device that has control of a priority type point.
The BACnet priority type points include: Analog Value Priority (AVP);
Binary Value Priority (BVP); Multi-State Value Priority (MSVP); Analog
Output (AO); Binary Output (BO); and Multi-State Output (MSO).
The WorkPlace Tech objects that represent these points are: Analog
Setpoint Priority (AVSPP); Binary Setpoint Priority (BVSPP); and any
object that represents a physical output point, namely Analog Output,
Binary Output, Event Indicator, Fan Speed, Floating Actuator, Floating
Actuator Priority, Momentary Start/Stop, PWM, PWM Priority, and VAV
Actuator.
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The Type of Point
Affects COV
Efficiency
The use of priority type points for UNC or ENC COV subscription is not
recommended. A UNC or ENC will poll all outputs, as well as the analog
value priority and binary value priority type objects. The rewrite mechanism
requires that all points be polled that are a priority type, even if those points
are COV subscribed. Using COV for priority type points will not reduce
message traffic or decrease update times, therefore this action would negate
any benefit of using COV for these points. For this reason, you should allow
only non-priority type points to have their useCOV property set to True.
Refer to the list of priority type points at the end of the preceding section,
"Choose the Right covIncrement Value".
Summary
Firmware releases 1.3 and 1.4, and later, for MNB-xxxx controllers have the
potential to increase speed performance via two mechanisms – more
efficient communication and COV subscription.
Note: COV Functionality and Firmware Versions
• COV server functionality was added to the Unitary and VAV controllers
in firmware version 1.3.
• COV server functionality for the Plant Controller was added in firmware
version 1.4.
• COV client functionality was added to all controllers in firmware version
1.4.
The steps you must take to utilize the performance potential of firmware 1.3
and later are as follows:
1. Upgrade the MNB-1000 to firmware 1.31 if an MNB-1000 is used as an
MS/TP router.
2. Upgrade all MNB-300 and MNB-Vx controllers to firmware 1.3 or later.
3. Set the useCOV property of all BACnet objects (both device and point) to
True. Use the AdminTool object to set all (or many) of the objects at the
same time, as follows.
Note:
• Devices learned after the upgrade will have the useCOV property
enabled.
• Points, whether they’re learned before or after the upgrade, will have
COV disabled. This is because learning a device’s points results in
the useCOV property of those points being set to their default value,
False. The useCOV property must then be manually changed to
True.
a. Secure a station backup.
b. Copy and paste the AdminTool object into the station.
c. Open the AdminTool object property sheet.
d. Enter the rootNode string.
e. Enter “useCOV” as the propertyName.
f. Enter the newValue, True.
g. Set recurseChildren to True.
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h. Set the optional filter properties to select desired points, if needed.
i.
Choose SearchAndReplace in the Commands menu.
4. Set the useCOV property of oft-written point objects back to False.
5. Restart the UNC or ENC. This is a precaution to ensure that COV
subscription starts in an orderly manner.
6. Verify that the covIncrement value is appropriate for the different point
types and purposes.
Note:
• Degrees temperature will not use the same covIncrement as inches
of water column.
• Do not use COV subscription for priority type points.
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Setting Up a Remote I/O Network
Overview
The I/O count of an MNB-1000 controller can be greatly expanded by
connecting a network of one to eight MNB-1000-15 remote I/O modules to
its remote I/O port. To do this, you:
1. Address the I/O modules (see “Addressing Limit” on page 45).
2. Wire the modules to the controller.
3. Confirm that the controller’s firmware has been upgraded to version 1.5
or later.
4. Download an application that includes remote I/O modules, to the
controller.
The modules will be learned and configured automatically. If any modules
are to be added or removed at a later time, this can be done manually,
through the ADI/Remote IO Wizard of the WorkPlace Tech Tool (must be
version 5.7 or greater). For detailed instructions on adding or removing
remote I/O modules in an MNB-1000 application, refer to the WorkPlace
Tech Tool BACnet Engineering Guide Supplement, F-27356.
Note: Refer to “MNB-1000-15 Remote I/O Module” on page 13 for more
information on the remote I/O module.
Installing Remote I/O Modules
Physically install and wire remote I/O modules according to the detailed
instructions in the MNB-1000-15 Remote I/O Modules Installation
Instructions, F-27486.
Configuring Remote I/O Modules
Configure the MNB-1000 application for remote I/O modules according to
the WorkPlace Tech Tool BACnet Engineering Guide Supplement, F-27356,
and WorkPlace Commissioning Tool and Flow Balance Tool User's Guide,
F-27358.
The Remote I/O Network
The connection of remote I/O modules to an MNB-1000 constitutes a
communications network that is unrelated to any other network. Therefore,
the existence of these modules is transparent to the MS/TP network (or any
other BACnet network) to which the MNB-1000 is connected. For all intents
and purposes, the controller and its modules can simply be viewed as an
MNB-1000 controller with expanded I/O.
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Appendix A
Understanding the Transmit and Receive Data LEDs on
Remote I/O Networks
Observation of a module’s transmit data (XMT) and receive data (RCV)
LEDs can be very helpful when troubleshooting certain situations on a
remote I/O network. An understanding of the request-response sequences
allows you to make some reasonable assumptions about how the network is
performing.
Note:
• The XMT LED on the remote I/O module is green, and the RCV LED is
amber. See Figure–3.1 on page 55.
• In EIA-485 (RS-485) communications (such as remote I/O), “TxD” and
“RxD” are traditionally used in reference to transmit and receive.
However, the corresponding common terms, “XMT” and “RCV,” appear
on the labels of some MNB-xxxx devices, and therefore will be used
throughout this document.
Remote I/O Modules
Communication between an MNB-1000 controller and an MNB-1000-15
remote I/O module occurs by request and response. That is, when a module
receives a query from the controller, it immediately sends a response,
flashing the XMT LED as it does so. The controller polls all eight remote I/O
module addresses in order, once every 1.6 seconds, whether or not there
are modules associated with those addresses. The RCV and XMT LEDs of
the remote I/O module indicate active communication as follows:
• The RCV LED will appear to be nearly solid ON but will flash (flicker)
very rapidly, and it will momentarily flash OFF while the module
transmits a response (XMT LED flashes ON). These flashes indicate all
activity on the remote I/O network, whether that activity is initiated by the
module being watched, another module on the network, or the
MNB-1000.
• The XMT LED flashes (or flickers) in a fairly consistent pattern. Each
flash indicates that the module is transmitting in response to a request
from the MNB-1000.
In General
Generally, remote I/O network communications problems are indicated as
follows:
XMT LED and RCV LED (both)—No Flashing: Any time there is no
activity (no flashing) from both the XMT LED and the RCV LED, we know
that the module is no longer communicating with the remote I/O network.
This lack of response is usually due to a wiring problem, or it may be that the
MNB-1000 to which the module is connected is not configured for remote I/O
modules.
XMT LED—Continuous Flashing, RCV LED—No Flashing: Any time the
XMT LED is flashing continuously, without any flashing from the RCV LED,
we know that: a bad module whose XMT LED is not working; or the device is
not a remote I/O module but, instead, an MNB-300 controller that was wired
to the remote I/O network by mistake.
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XMT LED—No Flashing, RCV LED—Continuous Flashing: Any time that
the RCV LED is flashing continuously, without any flashing from the XMT
LED, we know that: the remote I/O module has a fault that prevents it from
communicating; the module has an address greater than “8,” which would be
accompanied by a solid red Status LED; or the module is connected to a
network other than a remote I/O network, such as an MS/TP network.
RCV LED—Mostly OFF: If the RCV LED is flashing in a pattern where it is
off a good portion of the time (with or without the XMT LED), a serious wiring
issue is present.
Remote I/O Best
Practices
EOL Resistors
The MNB-1000 controller and the MNB-1000-15 remote I/O module are both
equipped with a jumper-selectable EOL termination resistor (marked
“IO EOL”) for the remote I/O network. When connecting a remote I/O
network to an MNB-1000 controller, be sure to set the EOL termination
resistor at the devices at each end-of-line. Do not set an EOL at any other
location. The default position for the remote I/O network EOL jumper is
“Disable.”
Bias Resistors
The MNB-1000 controller has a pair of permanently enabled, built-in bias
resistors that provide the bias to the remote I/O network. Do not use any
other bias resistors, including the jumper-settable bias resistors located
under the cover of the MNB-1000-15 remote I/O module.
Fallback Function
The MNB-1000-15 module’s outputs are driven by the application in the
MNB-1000. However, in cases where there is a temporary loss of
communication between the module and the MNB-1000, a fallback function
provides output values to the MNB-1000-15.
During normal communication, fallback output values are sent by the
MNB-1000 to the remote I/O module, where they are stored. If
communication between the module and the MNB-1000 is lost, the module’s
outputs are set to these values. These values remain in effect until
communication is restored.
The fallback function applies fallback values as follows:
• The remote I/O module has a default state of OFF for all DOs and a
default state of 0% for all AOs. However, the user may define other
values (fallback values) for these outputs during configuration of the
MNB-1000 controller’s application. The MNB-1000 writes, to the
module, any such user-defined fallback values that are associated with
remote I/O hardware tags.
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• During initialization following a power reset, before communication is
restored between the MNB-1000 controller and the remote I/O module,
the module will apply the default state (see above) to all its outputs.
Once communication is re-established, the controller re-initializes the
remote I/O module and downloads the user-defined fallback values (if
there are any) to the module. For those modules that are not configured
in the MNB-1000’s application, the controller will not re-initialize the
module or download the user-defined fallback values. Therefore, the
unconfigured remote I/O modules will use their default fallback value,
indefinitely, until such time that they are configured. Once the
re-initialization process is completed, the controller reissues, to the
remote I/O module, all output values as determined in the control logic.
• Whenever the module loses communication with the MNB-1000
controller for a specified time interval (the fallback time), it will apply the
fallback values to their associated outputs. If a user-defined fallback
value is available, it will be applied. If no user-defined values are
available, the default state will be applied, instead.
• Upon restoration of communication, the MNB-1000 controller reissues
all output values to the remote I/O module.
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Glossary
This section contains definitions, abbreviations, and acronyms that may be
used in this document:
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Actual IP Address
The IP address with which a device has been
configured. What the device knows as its own
address. Often known as the local IP address.
ANSI
American National Standards Institute
Apparent IP
Address
The IP address that appears to belong to a device.
This is the address that is used for accessing a
device from outside the LAN that the device resides.
The use of NAT dictates that the apparent address
will be different than the actual address. The
apparent IP address would usually be public IP
address.
ASHRAE
American Society of Heating, Ventilating,
Refrigeration, and Air-conditioning Engineers
AWG
American Wire Gage
BACnet/IP
see BACnet/IP
BACnet
Building Automation and Controls Network
BACnet Device
Any device, real or virtual, that supports digital
communication using the BACnet protocol.
BACnet Ethernet
BACnet over Ethernet – a method for encapsulating
BACnet messages with an Ethernet wrapper to be
transmitted on a network type that uses the Ethernet
protocol. BACnet Ethernet is non-routable.
BACnet
Internetwork
Two or more BACnet networks that are
interconnected with one or more BACnet routers.
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Appendix A
BACnet MAC
Address
A BACnet MAC is used as a physical address on a
BACnet network. The address must be unique on
the network. This address takes one of two forms,
either a one or six octet address. The form of the
address is determined by the network type.
A BACnet MAC from an MS/TP network will be just
one octet long (8 bits in length). This means it will
have a value ranging from 0 to 255 decimal, or 0 to
FF hexadecimal, for example, 63 (decimal) or 3F
(hexadecimal) represent the same value. The
MS/TP MAC address is the same as physical
address (DIP switch setting). It will be unique
because each separate MS/TP network must have a
unique network number.
A BACnet MAC from a BACnet/Ethernet network will
be the same as the network interface MAC, a
six-octet value that will normally be expressed as a
hexadecimal number with the octets commonly
separated by dashes, for example
00-13-CE-53-B3-E9 (hexadecimal).
If the BACnet MAC is from a BACnet/IP network, it
will be derived from the combination of IP address
plus UDP port number. This provides a six-octet
value (4 octets from the IP address plus 2 from the
port number), which when expressed in hexadecimal
will appear just like a BACnet/Ethernet MAC
address, for example 10.1.142.181:47808 (decimal)
or 0A-01-8E-B5-BA-C0 (hexadecimal)
BACnet Router
A device that communicates on two or more BACnet
networks and routes BACnet messages between
those networks. Do not confuse BACnet router and
IP router.
BACnet/IP
BACnet over IP – a method for encapsulating
BACnet messages with an IP wrapper to be
transmitted on a network type that uses Internet
Protocol (IP).
BAS
Building Automation System
B-ASD
BACnet Application Specific Device
BBMD
BACnet Broadcast Management Device – a device
used for transmitting BACnet broadcast messages
through IP router(s) to a different network or subnet
Bias Resistors
Also known as pull apart or pull up/pull down
resistors – provide a voltage differential on the
(EIA-485) communication conductors.
°C
Degrees Celsius
Device Identifier
Device object instance number.
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Device Object
This object makes information about the device and
its capabilities available to the other devices on the
BACnet internetwork. A device object is present in
every BACnet device.
DI
Digital Input
DIP
Dual In-line Package (switch)
DO
Digital Output
EEPROM
Electrically Erasable Programmable Read-Only
Memory
EMI
Electromagnetic Interference
EOL
End-Of-Line
EOL
End Of Line terminating resistor, the value used for
MS/TP is generally 120 Ohm. One is required at
each end of the communications bus. This is typical
of most EIA-485 (RS-485) networks.
Ethernet
IEEE 802.3 - A communication protocol and physical
network specification that is the basis for much of
today’s network infrastructure for business and
home LANs and WANs.
°F
Degrees Fahrenheit
FRAM
Ferroelectric RAM
ft.
foot
Global IP Address
An IP address capable of being used on networks
outside of the local network. Also see “Apparent IP
Address.”
GND
Ground (electrical)
HVAC
Heating, Ventilating, and Air Conditioning
Hz
hertz
I.D.
Inside Diameter
I/A
Intelligent Automation
I/O
Input / Output
Instance Number
A number used to identify a BACnet object. BACnet
object instance numbers must be unique within a
device per the object type. Device object instance
numbers must be unique within a BACnet
internetwork.
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Appendix A
Internetwork
Two or more networks connected by routers.
Networks in an internetwork share information and
services. An internetwork in the case of a BAS would
encompass all networks of devices that will
communicate with each other.
IP
Internet Protocol
IP
Internet Protocol – a common communication
protocol that is used extensively on the Internet and
widely used for home and business networking.
IP Router
A network device that forwards packets from one
network to another using the IP protocol.
Kb
Kilobit
KB
Kilobyte
kHz
kiloHertz
LCD
Liquid Crystal Display
LED
Light Emitting Diode
Local IP Address
An IP address used on a local network, this is
usually a private IP address. Also see “Actual IP
Address.”
m
meter
mA
milliAmperes
MAC
Media Access Control
MaxMaster
MaxMaster is a property that exists in all MS/TP
master devices. This property tells the device the
highest MS/TP address that may exist on the
network. The default value of this property is always
127.
MB
Megabyte
mm
millimeter
MS/TP
Master Slave Token Passing
MS/TP
Master Slave / Token Passing – a BACnet network
specification based on the EIA-485 (formerly
RS-485) standard
MS/TP Master
An MS/TP device that passes the communication
token to other devices. Any MS/TP master must be
capable of regenerating the token after a loss of
communication. All MNB devices are MS/TP
masters during normal operation.
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MS/TP Slave
An MS/TP device that does not pass the
communications token and communicates only
when an MS/TP master makes a request. An MNB
device is an MS/TP slave only while having its
firmware upgraded or anytime the address DIP
switch is set to 128 or greater.
n/a
Not Applicable
NAT
Network Address Translation – a method for
conserving IP addresses by assigning private IP
addresses on a LAN and using a NAT router to
translate those actual addresses to the apparent
(public) addresses that are outside the LAN, in other
words on the Internet.
O.D.
Outside Diameter
Object Identifier
An object identifier is the combination of an object’s
type and its instance number. Object identifiers,
other than device object, must be unique within a
BACnet device.
Octet
A binary number consisting of eight digits. An octet
is often expressed as either a decimal or
hexadecimal number for ease of human
understanding. The value of an octet may be from
00000000-11111111, these are the same as decimal
values 0-256 or hexadecimal values 0-FF.
PC
Personal Computer
PDF
Portable Document Format
pF
picofarad
Private IP Address
An IP address that is used on a private network that
is unregulated by the governing bodies that assign
addresses for the Internet.
Public IP Address
An IP address that is used on public networks
(Internet), these addresses are regulated to ensure
that each is unique. Also see “Apparent IP Address.”
RAM
Random Access Memory
RFI
Radio Frequency Interference
RH
Relative Humidity
RCV
Receive Data (LED)
RxD
Receive Data. This abbreviation is used in EIA-485
(RS-485) communications, such as MS/TP. Also see
“RCV.”
SDRAM
Synchronous Dynamic RAM
SPST
Single Pole Single Throw
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SRAM
Static RAM
TO
Triac Output
TxD
Transmit Data. This abbreviation is used in EIA-485
(RS-485) communications, such as MS/TP. Also see
“XMT.”
UI
Universal Input
Unicast
Communication between a single sender and a
single receiver over a network. A message sent
directly to a single device.
Unit Load
A measure of the electrical loading of an EIA-485
(MS/TP) network. An EIA-485 network may have 32
unit loads. One unit load consists of one full-load
transceiver, two half-load transceivers, four
quarter-load transceivers, or eight eighth-load
transceivers. All MNB-xxxx, UNC-xxx, and ENC-xxx
devices use quarter load transceivers, which means
that an MS/TP network comprised solely of MNB,
UNC, or ENC devices can have no more than 128
total devices (1 router plus 127 controllers).
32 unit loads times 4 transceivers per unit load
equals 128 maximum transceivers per network
(32 X 4 = 128).
UO
Universal Output
V
Volts
VA
Volt-Amp
Vac, Vdc
Volts Alternating Current, Volts Direct Current)
VAV
Variable Air Volume
VPN
Virtual Private Network – extension of a private
network that encompasses links across shared or
public networks, like the Internet, using a secure
tunnel. There are many types of VPNs. However, for
our use with BACnet/IP we mean remote access of a
computer to a private LAN, using a client/server
process through a tunneling protocol.
W.C.
Water Column
WP Tech
WorkPlace Tech Tool
WPFBT
WorkPlace Flow Balance Tool
WPCT
WorkPlace Commissioning Tool
XMT
Transmit Data (LED). Also see “TxD.”
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