CANopen Field Bus
78
Operating Manual XCx 300 / 500 / 540 Version 09/08
7.1.4
Lifeguarding
While nodeguarding is used by the guarding master to detect a failed
station, the monitored station uses these guarding telegrams to detect
a failed master. This monitoring function of the station is called
lifeguarding.
To detect a broken cable and enforce a shut-down of the outputs with
CANopen, the nodeguarding and lifeguarding functions must be
activated.
To activate lifeguarding the NMT manager must describe the Guard
Time (100Ch) and the Life Time Factor (100Dh) objects.
If the monitoring time
Life-Time = Life-Time-Factor * Guard-Time [ms]
expires without a guarding telegram arriving at the station, a guarding
error has occurred.
A RIO CANopen bus coupler or compact module switches the
NET LED to red flashing and shuts the outputs down.
A Schleicher PLC with CANopen signals the guarding error to the
PLC program using a function block.
If one of the above-mentioned objects is 0, no lifeguarding and no
cable break detection is carried out.
