Siemens S5-135U/155U appendix Status Indicators, Stop LED

CPUs, Memory Cards, Memory Submodules, Interface Submodules

Status Indicators

RUN LED

on

off

off

STOP

LED

off

on

off

Status

The CPU is in the RUN state.

The CPU is in the STOP state. After a stop request by switch or PG function, the STOP LED is continuously lit because the transition to the STOP state was requested by the user or, in multiprocessor operation, by another CPU, and was not caused by the CPU itself.

The CPU is in the INITIAL START or program check state.

LEDs for Fault Indication and Signaling

off	slow	The CPU is in the STOP state. The CPU has
	flashing	caused a transition to the STOP state (possibly
		also for the other CPUs). If you set the mode
		switch to STOP, the flashing LED becomes
		continuously lit.
off	rapid	The CPU is in the STOP state. An overall reset
	flashing	has been requested. This request can be initiated
		by the CPU itself or by operator action.

QVZ LED
on	During direct access or process image update, a module
	addressed by the program no longer acknowledges although
	S either it has acknowledged in single-processor operation
	upon reset of the CPU 928B in the area of the process
	image (IB 0 to 127, QB 0 to 127) and has been entered as
	present in the ª9th trackº (see Programming Guide,
	CPU 928B -3UB21),
	S or it has been entered in DB 1 (address list) in
	multiprocessor or single-processor operation and has been
	recognized as present during the reset.

Possible causes

SModule failure.

SModule was pulled out during operation, in the STOP state or in the Off state without a subsequent reset.

System Manual	5-37
C79000-G8576-C199-06