Which products are affected?
9300EP servo positioning controller as of Version V2.1
What happens?
The program fails to start.
When does the problem occur?
When the program control is in the 'Ready to start' state the positioning program can be restarted with a signal at input POS-PRG-START. To ensure that the rising signal was detected, there had to be a Low signal at POS-PRG-START in the 'Ready to start' state for at least one cycle.
If a particularly fast control (PLC) was being used, it was sporadically possible that the start signal was set too early after the request for the 'Ready to start' state via the corresponding status outputs, it could not be detected and the program failed to start. This case only occurred if the positioning program had just been terminated one cycle previously.
Short-term measures/recommendations?
When the program control is in the 'Ready to start' state, the positioning program can be restarted with a signal at POS-PRG-START if it has not been started before. Wait at least one milisecond in the 'Ready to start' state before the start signal is send in order to ensure the start at the first signal.
Evaluation:
Uncritical because it is a special case which occurs very seldom in practice and then it is also easy to avoid.
