Beckhoff CX1500-M510 Manual page 95

Format of the Boot-up message
11 bit 1 byte of user data
identifier
0x700 0x00
(=1792) +
Node-ID
Node Monitoring
Node Monitoring
Heartbeat and guarding mechanisms are available to monitor failures in the CANopen network. These are of
particular importance for CANopen, since modules do not regularly speak in the event-driven mode of
operation. In the case of "guarding", the devices are cyclically interrogated about their status by means of a
data request telegram (remote frame), whereas with "heartbeat" the nodes transmit their status on their own
initiative.
Guarding: Node Guarding and Life Guarding
Guarding
Node Guarding is used to monitor the non-central peripheral modules, while they themselves can use Life
Guarding to detect the failure of the guarding master. Guarding involves the master sending remote frames
(remote transmit requests) to the guarding identifier of the slaves that are to be monitored. These reply with
the guarding message. This contains the slave's status code and a toggle bit that has to change after every
message. If either the status or the toggle bit do not agree with that expected by the NMT master, or if there
is no answer at all, the master assumes that there is a slave fault.
Guarding procedure
Protocol
Protocol
CX1500-M510, CX1500-B510 Version: 1.0
Product overview
95