Intro to
CANopen Networks
E. Zivi Nov 6, 2014
References:
1.
2.
3.
4.
5.
6.
7.
8.
A CAN Physical Layer Discussion Microchip Application Note AN00228a
Controller Area Network (CAN) Implementation Guide Analog Devices Application Note AN-1123
Controller Area Network, CANPRES Version 2.0 , Siemens Microelectronics, Inc., October 98
http://www.kvaser.com/en/about-can/the-can-protocol.html
CAN physical layer ref: http://www.can-cia.org/index.php?id=systemdesign-can-physicallayer
Controller Area Network Physical Layer Requirements, TI SLLA270–January 2008
CAN Tutorial, http://www.computer-solutions.co.uk/download/Peak/CAN-Tutorial.pdf
CANopen Introduction,
ref: http://www.canopensolutions.com/english/about_canopen/about_canopen.shtml
1. Embedded Networking with CAN and CANopen, by Pfeiffer, Ayre and Keydel
2. CANopen Implementation: Applications to Industrial Networks, by Farsi and Barbosa
3. CAN in Automation, http://www.can-cia.org/
Recall CAN & ISO/OSI
Reference Model
2
CAN in Automation (CiA) CANopen &
ISO / OSI Reference Models
CiA 401
Generic I/O
Profile
CiA 402
Motion Control
Profile
IEC 61131-3
Programmable
Devices Profile
CiA 4xx Device Profiles
CiA 302 CANopen Framework for CANopen
Managers & Programmable Devices
Application
CiA 301 CANopen Application Layer &
Communication Profile
Not Implemented by CAN or CANopen
ISO 11898 CAN Data Link Layer
ISO 11898 CAN Physical Layer
High level CAN Protocols implement Application layer and skip the four intervening layers
3
CAN &CANopen Protocol Layers
Application Layer
Device profile for
generic I /O
modules
(CiA 401, V3.0)
Device profile
drives and
motion control
(CiA 402, V2.0)
Interface and device
profile for IEC 61131...
3 programmable
devices
(CiA 405, V2.0)
...
CANopen application layer and communication profile (CiA 301, V4.1, EN
50325-4) CANopen framework for CANopen managers and programmable
CANopen devices (CiA 302, V3.4)
CAN data link layer (ISO 11898:2003)
CAN physical layer (ISO 11898:2003)
CAN Bus
We’ll investigate CANopen high level protocols after we have a basic understanding of CAN
4
CAN Higher Level Protocol Examples
1. CANopen : In the late 1990’s CANopen device profile specifications where
established. CANopen includes
a. A node addressing scheme
b. Communication protocols supporting network management, device monitoring
and communication between nodes
c. Application layer device profiles
2. SAE J1939 : In 1998, the Society of Automotive Engineers (SAE) published the J1939
application layer protocols on top of CAN for vehicle applications. J1939 based
standards include: truck and trailer communication (ISO 11992), agriculture and
forestry vehicles (ISO 11783) and marine navigation systems (NMEA 2000).
3. ARINC 825 : Newer commercial aircraft such as the Airbus A380 and the Boeing 787
4. DeviceNet : Allen-Bradley (now Rockwell Automation) created DeviceNet as an
application layer protocol on top of CAN in the 1990’s. DeviceNet CONFORMANCE
TESTED® products have been certified by the Open DeviceNet Vendors Association
(ODVA) to conform to the specification.
5
CANopen Attributes
1. Unique node IDs
1. 7 bits of 11-bit CAN Message ID is node address
2. 4 bits of 11-bit CAN Message ID is CANopen message type
2. Network Management (NMT) including NMT state
machine, Boot-up, Heartbeat
3. Service Data Objects (SDOs) for network management
4. Process Data Objects (PDOs) for real-time process data
5. Each node contains an Object Dictionary with pre-defined
entries for:
1. Node configuration
2. Process data
3. Mapping of process data to PDO messages
6. Electronic Data Sheets to automation network systems
integration
CANopen Network Management State
Machine
PDO
SDO
Sync
Timestamp
Emcy
NMT
Error
control
Stopped
Operational
Preoperational
Available
Services
Network States
MicroMod CANopen I/O
MicroMod CANopen
Preprogrammed I/O
Implements subset of DS401
CANopen Generic I/O
Specifications. Electronic Data
Sheet Configures system.
MicroMod CANopen Generic I/O Message Implementation
Comm Obj
Message
# of Data
Elements
TPDO 1
Message Data Type
I/O Definitions
1
unsigned byte
Digital In 0..7
RPDO 1
1
unsigned byte
Digital Out 0..6
TPDO 2
4
10 bits in unsigned ints
Analog In 0..3
RPDO 2
4
8 bit duty cycle in unsigned ints
PWM Out 0..3
TPDO 3
4
10 bits in unsigned int
Analog In 4..7
MicroMod CANopen DS-401 Generic Digital I/O
TPDO 1 & RPDO 1 Message Mapping
Transmit Process Data Object TPDO1 on change of any of 8 digital inputs
Digital Input
(8 bits)
TPDO1
(1 byte)
CID: 0011
nnnnnnn2
Data:
bbbbbbbb2
Update 7 bits of digital output upon Reception
of Receive Process Data Object RPDO 1
Digital Output
(7bits)
RPDO1
(1 byte)
CID: 0100
nnnnnnn2
Data:
xbbbbbbb2
MicroMod CANopen DS-401 Generic Analog
Input TPDO 2 Message Mapping
Transmit Process Data Object TPDO 2 on change
of any of Analog Inputs 0 thru 3
Resolution = 5V range / (210 – 1)
Data transmitted in
little endian (Least
Significant Byte
First) form
Analog Input 3
Analog Input 3
TPDO3 Provides a
second bank of 4
Analog inputs
Analog Input 3
Analog Input 3
TPDO2
(2 bytes)
(2 bytes)
(2 bytes)
(2 bytes)
10-bit Analog input is backed into 16 bit data words
CID: 0101
nnnnnnn2
Data:
BBBBBBBB16
MicroMod CANopen DS-401 Generic Analog
(PWM) Output RPDO 2 Message Mapping
Receive Process Data Object RPDO 2 changes
Duty Cycle of PWM outputs 0 thru 3
Resolution = 1 / (28 – 1)
Data transmitted in
little endian (Least
Significant Byte
First) form
PWM Output3
PWM Output3
PWM Output3
PWM Output3
RPDO2
(2 bytes)
(2 bytes)
(2 bytes)
(2 bytes)
8-bit PWM duty cycle is packed into every other byte
CID: 0101
nnnnnnn2
Data:
BBBBBBBB16
Constructing DS-401 Generic IO Message IDs
4-bit Msg ID + 7-bit Node ID
CANopen DS-401 Generic I/O 11-bit Message ID Format
Comm Objects
4-bit Msg ID
7-bit Node ID
DS-401 Generic I/O
Msg bits b10 … b7 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Definitions
NMT Service 0x000
0
0
0 0 0 0 0 0 0 0 0
SYNC Msg
0x080
0
0
0 1 0 0 0 0 0 0 0
Emergency
0x080
0
0
0 1 n6 n5 n4 n3 n2 n1 n0
Time Stamp
0x100
0
0
1 0 0 0 0 0 0 0 0
TPDO 1
0x180
0
0
1 1 n6 n5 n4 n3 n2 n1 n0
Digital In 0..7
RPDO 1
0x200
0
1
0 0 n6 n5 n4 n3 n2 n1 n0
Digital Out 0..6
TPDO 2
0x280
0
1
0 1 n6 n5 n4 n3 n2 n1 n0
Analog In 1..4
RPDO 2
0x300
0
1
1 0 n6 n5 n4 n3 n2 n1 n0
Analog Out 1..4
TPDO 3
0x380
0
1
1 1 n6 n5 n4 n3 n2 n1 n0
Analog In 5..8
RPDO 3
0x400
1
0
0 0 n6 n5 n4 n3 n2 n1 n0
Analog Out 5..8
TPDO 4
0x480
1
0
0 1 n6 n5 n4 n3 n2 n1 n0
Analog In 8..11
RPDO 4
0x500
1
0
1 0 n6 n5 n4 n3 n2 n1 n0 Analog Out 8..11
TSDO
0x580
1
0
1 1 n6 n5 n4 n3 n2 n1 n0
RSDO
0x600
1
1
0 0 n6 n5 n4 n3 n2 n1 n0
Heartbeat
0x700
1
1
1 0 n6 n5 n4 n3 n2 n1 n0
CANopen Motor Lab Configuration
CANopen
Magic
Node
Graphical User Interface
Bench
Power
Supply
CAN
Messages
Shaft
Rotation
Power
CANopen
MicroMod
Node
PWM
L298
Driver
Board
Motor
Modulated
Power
Encoder
Position Pulse
Analog Voltage Proportional to Motor Speed
Train
Frequency
to Voltage
Converter
Maxon Motor Tachometer Calibration
Angular Velocity (rad. / sec. ) = 37.41 (rad. / sec. / V) × Tachometer Output (V)
Tachometer Output is connected to MicroMod input Ain4
Maxon Motor Transfer Function
Using CAN Lab #3 Procedure
CAN Lab #3 CANopen Magic Window
Configuration
MicroMod Heartbeat, Operational & PWM Duty Cycle (with Function key) messages added
New Process Data visual display
Filtered Trace windows added