Siemens S5-135U/155U appendix LEDs for Fault Indication and Signaling, Possible causes

CPUs, Memory Cards, Memory Submodules, Interface Submodules

LEDs for Fault Indication and Signaling

Given in the following overview are the causes for LEDs lighting up:

QVZ LED
on	A module addressed by the program no longer acknowledges
	although/because
	S it either acknowledged in single-processor operation upon
	restart of the CPU 948 in the area of the process image
	(IB0 to 127, QB0 to 127) and has been entered as present
	in the so-called 9th track;
	S or it has been entered in multi or single-processor
	operation in DB 1 (address list) and has been recognized
	as present during the restart;
	S or it was addressed in direct access by operations LPY,
	LPW, TPY, TPW, LOY, LOW, TOY, TOW;
	S or the data handling blocks cannot access the module.

Possible causes:

SModule failure

SModule removed during operation, in the STOP state or in the Off state without subsequent restart.

	A timeout occurred during access to the user memory.
ADF LED
on	The user program has referred to an address in the process
	image under which no module was inserted in the I/Os or was
	not entered in DB 1 during the last restart.
ZYK LED
on	The preset cycle time monitor has responded and cyclic
	program processing is interrupted.
BASP LED
on	Command output is inhibited and the digital outputs will be
	directly switched to the safe state (0).

A detailed description of interrupt and error handling can be found in the CPU 948 Programming Guide.

System Manual	5-9
C79000-G8576-C199-06