System Description
Universal
Gateway
1.
Contents
1.
Contents ....................................................................... 3
2.
Document revision .......................................................... 4
3.
Foreword ....................................................................... 5
3.1.
Registered trademarks .............................................. 5
3.2.
Copyright ................................................................. 6
4.
Introduction................................................................... 7
4.1.
General on Gateways ................................................ 7
4.2. Field bus protocols .................................................... 8
4.2.1. The physical connection ....................................... 8
4.2.2. The communication protocol ................................. 8
4.2.3. Used data structures............................................ 8
4.3. Special functions ....................................................... 9
4.3.1. Mathematical links ............................................... 9
4.3.2. Logical links ........................................................ 9
4.3.3. Connection status ................................................ 9
4.4.
5.
What is a data point? ................................................ 9
Schematic structure of a Gateway .................................. 10
5.1.
Configuration of the interfaces .................................. 11
5.2.
Configuration of the drivers ...................................... 11
5.3.
Configuration of the special drivers ML and LL ............ 11
5.4.
The central dispatcher ............................................. 12
5.5.
Operating method of the Gateway software................ 12
5.6.
The data point “Connection status“ ........................... 12
6.
System functions of the Gateways .................................. 13
6.1. The project-ID ........................................................ 13
Structure of the project-ID ............................................ 13
Example of a project-ID ................................................ 13
6.2.
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Password protection ................................................ 14
MBS GmbH
Römerstrasse 15
D-47809 Krefeld
Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
2. Document revision
Rev-No.
1.0
Date
Author Remarks
01.07.2001 FRS
Initial version
MBS GmbH
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D-47809 Krefeld
Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
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4
3. Foreword
Thank you very much for using MBS Universal-Gateways. These
products enable the rapid and uncomplicated connection of different
field bus protocols. The following document gives an overview of the
possibilities of application of the Universal-Gateways.
3.1.
Registered trademarks
In this book trademarks and product names of specific companies are
used. The following terms are registered trademarks of the
respective vendors and are not especially mentioned in this book:

Microsoft, Windows and MS-DOS are registered trademarks of
Microsoft Corporation

BACnet and ASHRAE are registered trademarks of the American
Society of Heating, Refrigerating and Air-Conditioning Engineers,
INC. (ASHRAE)

Intel and Pentium are registered trademarks of the Intel
Corporation

ARCnet is a registered trademark of the Datapoint Corporation

IBM-PC and IBM-AT are registered trademarks of the International
Business Machines Corporation (IBM)

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16
LONTalk is a registered trademark of the Echelon, Inc.
MBS GmbH
Römerstrasse 15
D-47809 Krefeld
Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
3.2.
©2001
Copyright
MBS GmbH
Römerstraße 15
D-47809 Krefeld
Phone:
Telefax:
+49 / 21 51 / 72 94 - 0
+49 / 21 51 / 72 94 – 50
E-Mail:
Internet:
info@mbs-software.de
http://www.mbs-software.de
All rights reserved. No part of this book may be reproduced in any
form (printing, photocopy or any other technique) or processed,
duplicated or circulated electronically without written permission of
MBS GmbH.
MBS GmbH
Römerstrasse 15
D-47809 Krefeld
Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
6
4. Introduction
In the Building Automation different devices with varying
communication protocols and communication interfaces are used.
This may sometimes render difficult the common use of different
systems as compound or the connection of these devices to a
common data base, e.g. for higher management station systems.
By using MBS Universal-Gateways these problems may be solved
thus enabling the connection of different field bus protocols to a
compound or the translation from one protocol to another.
4.1.
General on Gateways
Gateways enable the translation of the data of a protocol to those of
another. These devices work like a universal translator who
(symbolically speaking) speaks all languages of the world fluently
and is able to translate them immediately into any other language.
Of course, in order to be able to speak all languages the translator
must have learned these before. In the Gateways the so-called
communication drivers assume this task (for each language, that
means each protocol, a special program).
A centralized dispatch layer ensures that the data are addressed
correctly. This procedure may be compared to the sending of a letter.
The address on the front page shows to whom the letter should be
sent and the back page shows who sent the letter.
So that the message reaches the recipient correctly you require
somebody who knows how to reach the addressee. This function may
be compared to that of a mailman. In Gateway also the drivers take
over this function. So that the drivers know how to transfer the
message (e.g. at what transfer speed) in Gateway a configuration is
defined for each connected system.
(This may be compared to a mailman´s route planning. The one
recipient lives directly in front of the post office, another recipient
may only be reached by bicycle or car.)
Of course, the MBS Universal-Gateways take into consideration the
specific circumstances of each protocol and even the special features
of certain devices.
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Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
4.2.
Field bus protocols
In general each field bus protocol may be divided into 3 different
areas.
4.2.1.
The physical connection
determines which media are used to transport the data, e.g. in
networks according to Ethernet-Standard via a shielded RG-58 cable
or cables twisted in pairs (TP-cable) or in serial connections via the
Standards RS232, RS422 or RS485. Here according to the protocol
used, maximum cable lengths or cable specifications have to be
considered.
4.2.2.
The communication protocol
determines how data are sent from one participant to another. For
this, data telegrams so-called „Messages“ are used. According to the
used protocol different messages are used, many protocols
additionally secure the data transfer by using check sums, that
means, before execution the recipient checks whether the data
telegram has been transferred correctly.
4.2.3.
Used data structures
Depending on the scope of efficiency the devices deposit their data in
different ways within the devices. Depending on the data protocol for
this exist normed or common specifications e.g. at BACnet objects or
at LONTalk SNVT’s (Standard-network variables). If no specifications
exist as is the case at MODBUS or Profibus-FMS, it is necessary to
know the used data structures. Most vendors disclose these in a
documentation about the used data structures.
MBS GmbH
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D-47809 Krefeld
Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
8
4.3.
Special functions
4.3.1.
Mathematical links
Depending on the protocol it is necessary to execute special functions
already when executing the transfer to another protocol. Examples
for this would be the conversion of measured values to other
measurement units or the scaling of measured values.
This functionality can be reached already on the Gateway level by
means of the module “Mathematical links“. Nearly all mathematical
functions of a Standard-PC may be used. With that you have a
powerful tool for conversion and scaling of values at your disposal. In
addition to the original values, the data points resulting from the
links are at your disposal as virtual data points of the Gateway and
may be processed in the same way as all other values.
4.3.2.
Logical links
More interesting possibilities are offered by the module “Logical
links“.
With this module binary values may be linked logically (AND, OR;
NOT, and so on) or the logic may be negated.
The values resulting from these links are also available for processing
as virtual data points.
4.3.3.
Connection status
In order to be able to supervise the connection, that means the
correct function of the Gateway, the status of the connection is
offered additionally to the data points of the respective protocol as
virtual data point. This enables to recognize break-downs of devices,
power interruptions or other occurring problems in time and to take
suitable measures.
4.4.
What is a data point?
As data point in the sense of the Gateway we understand a single
value respectively a single quantity which may be linked via the
dispatcher with another value or quantity. Of course, a single value
may also be allocated to different drivers for several times.
This data point allocation from, respectively to different drivers is
also referred to as “data point list“.
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Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
5. Schematic structure of a Gateway
The following diagram describes schematically the functions and
modules of a Gateway.
Special
Driver, e.g.
mathematical
links
Driver
e.g.
BACnet-Server
Central Dispatcher
Driver
e.g. Counter
via
M-BUS
MBS GmbH
Römerstrasse 15
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Interface
Configuration
Driver
e.g.
Profibus-DP
Slave
Tel.: +49 / 21 51 / 72 94-0
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www.mbs-software.de
10
5.1.
Configuration of the interfaces
Each driver program requires a configuration of the connected
interface used for the respective protocol. For a serial interface
among others the baudrate, the data bits, the parity, the stop bits
and so on are determined.
The configuration is stored in a text file named “driver.txt“.
For hints concerning the configuration of the interfaces please refer
to the documentation “Configuration of the interfaces“.
5.2.
Configuration of the drivers
For the configuration of the data points of a protocol one text file is
available per driver. In order to take into consideration the special
features of each protocol, the structure of this file is especially
coordinated with each protocol and thus different for each protocol.
A driver´s configuration of the data points is also stored in a text file,
the name of this file consists of the protocol name, e.g. “Ion“, a
consecutive number from 1-9 as each driver may be started up to 9
times, as well as the ending “.txt“.
So e.g. the name “mbus3.txt“ indicates the configuration of the third
M-Bus driver. This means that this file contains those data points
which may be represented via the M-Bus. These data points may be
linked with the data points of other drivers in the dispatcher.
For hints concerning the configuration of the drivers please refer to
the documentations ”Configuration of the driver XXX”.
5.3. Configuration of the special drivers ML
and LL
The special drivers mathematical and logical links are also projected
in a text file, however the data points made available by these
drivers do not represent any real but virtual values (that means
values resulting from the link). However, for the whole system this
does not make any difference, virtual data points may be linked and
processed in the same way as real data points.
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5.4.
The central dispatcher
The central dispatcher provides for the linking of the data points from
the various drivers. For this purpose the dispatcher receives a data
point list consisting of 1:1 allocations of single data points from the
different drivers.
The data format which will be exchanged between the drivers has
deliberately been restricted to the native basic data types that means
analog input-parameter, analog output-parameter, binary inputparameter, binary output-parameter and so on. This procedure
ensures that data from completely different systems and different
protocols can be interlinked.
The configuration of this data point list is stored in a text file named
“dispatch.txt“.
For hints concerning the configuration of the data point list please
refer to the documentation ”Configuration of the data allocation”.
5.5. Operating method of the Gateway
software
When starting the Gateway software the central dispatcher reads the
configuration of the interfaces from the file “driver.txt“ and then
starts the used driver programs. These determine by themselves
their respective data point configuration from the corresponding
driver configuration file.
After that the data points projected in the data point list are loggedin into the driver by the dispatcher.
The drivers work event-oriented, that means after log-in they report
changes of values independently to the dispatcher who takes care
that this change of value is dispatched to the respective driver which
has been projected in the 1:1 link. If several destinations have been
projected these are informed about the change of value in the
sequence of the projecting.
The drivers take over independently the forwarding of this change of
value in that protocol for which they have been concepted.
5.6.
The data point “Connection status“
Each driver has a virtual data point giving information about the
status of the connection to the respective protocol. With this data
point (“failure“) a supervision of the correct function of the respective
connected devices may thus be realized.
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6. System functions of the Gateways
6.1.
The project-ID
The project-ID allows the control whether the configuration files
correspond to the software drivers projected in the Gateway. This
system prevents that unvalid configurations can be used which might
result in malfunctions.
Structure of the project-ID
a) Static part
1. Checksum 16 Bit CRC
characters hex.
2. Customer number from KHK
characters hex.
3. Procedure number from KHK
characters hex.
4. Consecutive number within the procedure
characters hex.
5. Amount of data points
characters hex.
b) Variable part
6. supported protocols in ascending sequence
characters hex.
4
4
4
2
2
each 2
You will receive the project-ID from MBS GmbH when placing your
order.
Example of a project-ID
1741-0001-000101-c8-01010406
This project-ID describes a Gateway with up to 2,500 data points
with the software protocols.



LON (twice)
M-BUS
BACnet-Server
Customer and procedure number have been selected by coincidence
in this example.
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www.mbs-software.de
6.2.
Password protection
In order to protect your projecting efficiency against unauthorized
access or improper use a password may be deposited in the
Gateway. Thus gaining access is only possible if the correct password
has been entered otherwise access will be refused.
Hint: If the password has been lost, the password protection can
only be cancelled by the vendor.
MBS GmbH
Römerstrasse 15
D-47809 Krefeld
Tel.: +49 / 21 51 / 72 94-0
FAX: +49 / 21 51 / 72 94-50
www.mbs-software.de
14
MBS GmbH
Römerstrasse 15
D-47809 Krefeld
www.mbs-software.de
info@mbs-software.de