
9 | More about CANopen?
STÖBER
48
09/2019 | ID 442637.01
9.3.4.2
Heartbeat
The alternative to the life/node guarding mechanism is the heartbeat service. The advantage of this service over the life/
node guarding is that no remote frames are exchanged between the controller and drive controller—which considerably
reduces the utilization of the CAN bus.
2. Write-Heartbeat-Request
(Indication)
Producer-
Heartbeat-
Time
(Indication)
Consumer-
Heartbeat-
Time
1. Write-Heartbeat-Request,
1 Byte-Data:
(COB-ID = 1792 + Node-ID)
Bit Bit
7
t
6...0
s
Life-Guarding-
Event
Producer
(drive controller)
Consumer
(controller)
To enable detection of communication failures, a CAN bus node (usually a drive controller) independently transmits cyclical
messages (heartbeat protocol), which display its own operating state. Thus the drive controllers act as producer, while the
controller acts as consumer. During the transmission, it is necessary to maintain a defined time interval (producer heartbeat
time), within which a message has to be received. The consumer expects regular messages from the producer. If these fail
to appear, a heartbeat event is triggered.