Eliminated from:
EPL-10200 (Drive PLC) from V8.3 onwards
Behaviour of the new version?
A PR5 trip does not occur if the run-time of the user task with the longest interval time does not exceed 300 ms and the utilisation of the Drive PLC does not exceed 80 %.
Due to optimisations of the operation system of the Drive PLC the probability that a PR5 trip occurs could be reduced.
What happens?
A PR5 trip (C0168/1=76) occurs after the parameter set has been saved. The parameter set has not completely been stored safe against mains failure. In order to reset the trip the Drive PLC needs to be disconnected from the mains.
When does the problem occur?
The Drive PLC is internally equipped with a watchdog that monitors that the parameter set is stored safe against mains failure. If it takes too much time to save the parameter set the watchdog cancels the saving process with a PR5 trip. Thanks to this watchdog the Drive PLC can detect a defect memory for example.
However, the watchdog may also trigger if the run-time (not the interval time) of a user task is larger than 50 ms.
A longer run-time of the cyclic task (PLC_PRG and subprograms) cannot trigger a PR5 trip.
Which products are affected?
EPL-10200 (Drive PLC) V8.2 and lower
Possible diagnostics?
Check if the Drive PLC indicates error number 76 via C0168.
Short-term measures/recommendations?
- Avoid cyclically executing the Save parameter set command (C0003 = 1).
- The run-time of a user task should not exceed 50 ms.
- If a PR5 trip occurs, repeat saving the parameter set.
Evaluation:
Depending on the utilisation of the Drive PLC it may happen that a PR5 trip occurs, i. e. the parameter set has not completely been stored safe from mains failure. In order to reset the trip the Drive PLC needs to be disconnected from the mains.
