Siemens S5-135U/155U appendix Executing a Reset at all CPUs

Multiprocessor Operation/Coordinators

Step 7 Executing a RESET at all CPUs:

Action

Execute a RESET at each individual CPU:

Hold the MC 1) mode switch at the RESET setting; simultaneously set the mode switch from STOP to RUN.

Reaction

The red STOP LED on each CPU is continuously lit; each CPU emits the output inhibit signal. The CPUs are in the wait state.

	1) MC: Momentary-contact
Possible Faults	Symptom 1:
	The STOP LED of one CPU flashes slowly. When the control bits of this
	CPU are read out with the programmer, ªDB 1 errorº is marked in addition to
	the usual information. There is no output of an ISTACK.
	Remedy:
	Check whether data block DB1 in the CPU was correctly loaded and
	programmed.
	Symptom 2:
	After execution of a RESET:
	Undefined states or faults occur at the CPUs (e.g. after a RESTART at
	CPU 922, it goes to the RUN state although the other CPUs are still at
	STOP).
	Remedy:
	Verify the following points:
	S Is the coordinator inserted?
	S Are all modules correctly inserted (engaged)?
	S Are all modules at the correct slots?

System Manual	6-11
C79000-G8576-C199-06