iR-COP
5
5
Communication Error Control
5.1
Introduction
Node Guarding protocol and Heartbeat protocol can be used to detect device failures
on a CANopen network, please use one of these two protocols at a time.
5.2
Node Guarding Protocol
With Node Guarding, a certain network node (NMT-master) sends a remote transmit
request to the other nodes (NMT-slave) in the network one after the other (polling)
at defined intervals (Node Guard Time). The NMT-slaves respond to the request by
transmitting a data telegram with its current communication state: Pre-operation,
Operation, Stopped, within a certain time (Node Life Time). The format of the
telegram is as below:
Bit7
Bit6~Bit0
Toggle bit.
4: Stopped
5: Operational
127: Pre-operational
Node Life Time is calculated by multiplying two parameters: Guard Time and Life
Time Factor.
Node Life Time = Life Time Factor x Guard Time (ms)
Guard Time
Index
Sub Index
Data Type
Default Value
Description
100Ch 00h
UNSIGNED16 0000h
0:Disable
Master
Slave
Remote request
indication
response
request
confirmation
N
o
d
e
g
u
ar
d
in
g
tim
e
indication
indication
Guarding event
CAN-ID = 1792 + Node-ID
