Appendix C CANopen Protocol
C
Initialization Pre-operational
Operational Stopped
SDO
SYNC
X X
X X
The format of the control message for the node state:
COB-ID Byte 0 Byte 1
0 Command specifier (CS)
Slave address
(0: Broadcast)
The command specifiers are listed below.
Command specifier (hex)
Function
01
Start the remote node
02
Stop the remote node
80
Enter the pre-operational state
81
Reset the application layer
82
Reset the communication
Error Control services
The error control service is used to detect the disconnection of the node in the network. The error
control services can be classified into two types, Heartbeat and Node Guarding. The PLC only
supports Heartbeat. For example, the master can detect the disconnection of the slave only after the
slave enables the Heartbeat service.
The Heartbeat principle is illustrated as follows. The Heartbeat producer transmits the Heartbeat
message according to the Heartbeat producing time which is set. One or more Heartbeat consumers
detect the message transmitted by the Heartbeat producer. If the consumer does not receive the
message transmitted by the producer within the timeout period, the heartbeat event generated
indicates that the CANopen communication is abnormal.
C-5