1. CAN CANopen

2. History
1986
Robert Bosch GmbH introduced CAN protocol at the Society of Automotive Engineers (SAE) congress
1987
First CAN controller chips from Intel and Philips Semiconductors
Epec 2G CAN Modules in 1991

3. CAN Controller Area Network Standardized serial bus protocol
ISO (CAN Data Link Layer and Physical Signaling)
Use
automotive applications
industrial automation
medical equipment

4. CAN and ISO/OSI model CAN protocol defines following OSI layers
Data link (OSI 2)
Physical (partly) (OSI 1)

5. CAN physical layer standards
ISO high speed
the most used physical layer standard for CAN networks
implemented as CAN high-speed
the data rate up to 1 Mbit/s

6. CAN physical layer standards
ISO fault-tolerant
baud rate < 125 kbit/s
for this specification a short network was assumed, the problem of signal reflection is not as important as for long bus lines

7. CAN physical layer standards
SAE J2411 single wire
for CAN network applications with low requirements regarding bit rate (33,3 kbit/s) and bus length
ISO point-to-point
defines a point-to-point connection for use in e.g. towing vehicles and their trailers

8. Some terms
COB-ID
Communication Objects (COB) are uniquely identified in a CAN network by a number called the COB-ID. The COB-ID also determines the priority of the object.
NODE-ID
Unique ID number of a device in CANopen network
EDS
Electronic data sheet
describes the communication behaviour and the object dictionary entries of a device
Allows service tools, configuration tools, development tools, and others to handle the devices properly
DCF
Device configuration file
almost identical to the EDS
stores the configuration parameters of a specific node
can include minimum, maximum and default values for each entry

9. CAN basic concept Two communication services Broadcast Communication
the sending of a message
the requesting of a message
Broadcast Communication
All CAN nodes can receive all messages on the CAN bus
After receiving a message, the node decides if the message has to be accepted or not

10. CAN basic concept CAN frame formats
Standard, 11-bit identifier field
Extended, 29-bit identifier field
The 11-bit message always has priority over the 29-bit message
The implementation must accept the base frame format
The extended frame format must be at least tolerated

11. Standard/extended frames

12. CAN Frame Types
Data frame carries the data from a transmitter to the receivers
Remote frame is a frame requesting the transmission of a specific identifier
Error frame is transmitted by any unit on detecting a bus error
Overload frame is used to provide for an extra delay between the data and/or remote frame

13. Higher layer implementations
As the CAN standard does not include tasks of application layer protocols, such as
device addressing
transportation of data blocks larger than one message
application data
implementations of higher layer protocols were created

14. CAN protocols CANopen (www.can-cia.org) SAE J1939 (www.sae.org)
Industrial automation
SAE J1939 (
Heavy road vehicles
ISOBUS (
Agriculture
DeviceNet (

15. CANopen

16. CANopen
CAN-based higher layer protocol for distributed automation systems
Standardized (EN )
Specifies
communication protocols (NMT, SDO, PDO etc)
device profiles (CiA 401, 402, 405..) for typical devices of distinctive application areas

17. CANopen is used Machine control Factory automation
Laboratory automation
Transportation and traffic
Utility vehicles
Building automation
Medical Systems

18. CANopen benefits Guarantees an interchangeability of devices
Enables the communication between devices of different manufacturers
Standard features
Transmission of time-critical process data
Device description in OD
Device monitoring
Error signaling
Network management
Pre-defined connection set

19. CANopen internal device structure
A CANopen device can be logically structured in three parts

20. CANopen internal device structure

21. OD = Object Dictionary
OD is the most important part of any CANopen device
The interface between the application and CAN bus
Grouping of objects (parameters) accessible via CAN in an ordered and pre-defined way
Addressed with index and sub-index

22. OD = Object Dictionary
Each CANopen device implements a CANopen protocol stack
Usually implemented on the same micro-controller that is used by the device's application software

23. OD layout Index range Use Description 0000h Reserved 0001h – 025Fh
Data types
0260h - FFFh
1000h - 1FFFh
Communication object area
Describes the communication behavior of the device
2000h - 5FFFh
Manufacturer specific area
Describes the application behavior in a manufacturer specific way
6000h - 9FFFh
Device profile specific area
Describes the application behaviour in a standardized way by following a CANopen device or application profile
A000h - BFFFh
Interface profile specific area
Defines the network variables and system variables according to the related CiA interface specification
C000h – FFFFh

24. Node identification
All nodes are uniquely identified by node identification number
Node-ID value range is 1-127
CANopen systems can have 127 different nodes
No node-ID may exist twice

25. Master/Slave relationship
Every CANopen system has to have one Master node
Master unit typically can
Start or stop the network
Monitor the network
There can be multiple slaves in system
Normally the only special function of the CANopen Master is the starting of the network

26. Communication protocols
Process Data Objects (PDO) protocol
Service Data Objects (SDO) protocol
Network Management (NMT) protocols
NMT Message protocol
Boot-Up protocol
Error Control protocol
Special Objects protocols
Synchronization (SYNC) protocol
Time Stamp (TIME) protocol
Emergency (EMCY) protocol

27. Process data objects (PDO)
Used for broadcasting high-priority control and status information
Consists of one CAN frame  8 bytes of data
Communication: point to multipoint

28. Process data objects (PDO)
Triggering PDOs
Event or time
Synchronous/asynchronous
transmission
Remotely requested (RTR)
The PDO consumer must know what PDO to receive and what bytes contains the needed data

29. Predefined connection set
CANopen standard defines a pattern for message identifiers
1st PDO COB-ID = 180h + node-ID
2nd PDO COB-ID = 280h + node-ID
3rd PDO COB-ID = 380h + node-ID
4th PDO COB-ID = 480h + node-ID

30. Service data objects (SDO)
Service data objects (SDOs) enable access to all entries of a CANopen OD
The communication is point-to-point
The basic idea is that the SDO client sends request and the SDO server responses to the request

31. Special protocols
The SYNC object enables synchronous network behavior.
Synchronous PDOs use the SYNC message as triggering event for PDO transmission
The TIME, Time-stamp, object is used for the adjustment of a unique network-time
The EMCY, Emergency, object can be used to inform other network participants about device-internal errors 

32. Network management (NMT)
CANopen provides services and protocols for
controlling of the communication state of the nodes
monitoring nodes
The network management Master can control the communication state of the other nodes with NMT messages
NMT messages has the highest priority message identifier (CAN-ID 0)

33. Network management (NMT)
The NMT message consists of two bytes:
The command byte (start / stop/ …)
The node-ID whose communication state is to be changed
 COB-ID
BYTE 0 / CMD
BYTE 1 /NODE-ID
 000
0x01 Start
0x00 (All)
0x02 Stop
0x01 (Node-ID 1)
0x80 Preoperational …
0x81 Reset node
0x7F (Node-ID 127)
000
0x82 Reset communications

34. NMT states and transitions

35. Network management (NMT)
The NMT state machine defines the communication behavior of the CANopen device
State
NMT
SDO
PDO
Init -
Pre-Operational x
Operational
Stopped

36. CANopen device monitoring
Heartbeat principle
a node automatically transmits its communication state (NMT) at regular intervals as evidence of its communication ability
Transmitted cyclically with
COB-ID = 0x700 + node-ID
Recommended by CiA (node guarding is no longer used)

37. Predefined connection set
Communication object
COB-ID (hex)
Slave nodes
NMT
Receive only
SYNC 80
EMCY
80+NODE-ID
Transmit
TIMESTAMP
100
PDO
180+NODE-ID
1. Transmit PDO
200+NODE-ID
1. Receive PDO
280+NODE-ID
2. Transmit PDO
300+NODE-ID
2. Receive PDO
380+NODE-ID
3. Transmit PDO
400+NODE-ID
3. Receive PDO
480+NODE-ID
4. Transmit PDO
500+NODE-ID
4. Receive PDO
SDO
580+NODE-ID
600+NODE-ID
Receive
NMT node monitoring
700+NODE-ID

38. Basic OD entries Index Sub-index Type Description 0x1000 U32
Device type
0x1008
STRING
Manufacturer device name
0x1009
Manufacturer HW version
0x100A
Manufacturer SW version
0x1010
Store parameters (”save”)
0x0 U8
Number of entries
0x1
Save all parameters
0x2
Save communication parameters
0x1011
Restore default parameters (”load”)
Restore all default parameters
0x1016
Consumer heartbeat time
0x1 – 0x7F
0x1017
U16
Producer heartbeat time

39. Basic OD entries Index Sub-index Type Description 0x1018
Identity object
0x0 U8
Number of entries
0x1
U32
Vendor-ID
0x2
Product code
0x3
Rev. Number
0x4
Serial number
4G communication parameters (2020, 2023, 2024, 2038)
0x2003
Node-ID for CAN1
Bit rate for CAN1
0xD
Node-ID for CAN2
0xE
Bit rate for CAN2

40. Basic OD entries 3000, 4602, 5050, i10, 6000 communication parameters
Index
Sub-index
Type
Description
0x2150
CAN1 configuration
0x0
U16
Number of entries
0x2
CODESYS communication node-ID
0x3
Bit rate
0x4
Cable detection offset for CODESYS node-ID
0x5
Cable detection offset for PLCopen node-ID
0x6
Mask for the cable detection pins
0xA
PLCopen application node-ID in CAN1
0x2151
CAN2 configuration (if exists, see sub-indexes above)
0x2152
CAN3 configuration of 5050, see sub-indexes above
0x2153
CAN4 configuration of 5050, see sub-indexes above

41. Source CAN in Automation CiA Standards 301 & 302
CiA Standards 301 & 302
IXXAT
Wikipedia: CAN, CANopen