Step 4; Step 5 - Siemens S5-155U System Manual

Step 4

Possible faults

Step 5

System Manual
C79000-B8576-C199-03
Action
Switch the supply voltage on.
Symptom:
On some CPUs the STOP LED is not lit; the other CPUs are
requesting OVERALL RESET. All CPUs are emitting the BASP
(output inhibit) signal.
Remedy:
Check the setting for the number of occupied CPU slots on the
coordinator. Are the CPUs inserted at suitable slots?
Executing an OVERALL RESET on all CPUs:
Ensure that the mode switch on the coordinator is set to STOP.
(Precondition: Steps 3 and 4 have been fully executed.)
Action
Execute the OVERALL RESET
for each individual CPU:
1)
Hold the MC mode switch in
the OVERALL RESET setting;
simultaneously set the mode
switch from STOP to RUN and
back to STOP.
1)
MC: Momentary-contact
Starting the Multiprocessor Operation
Reaction
1. The red STOP LEDs flash
rapidly on all CPUs to
indicate: Overall reset
requested.
2. If the test mode is not set
at the coordinator (see
Section 6.3) and the mode
switch is not at the TEST
setting:
The red BASP (output
inhibit) LED is permanently
lit to indicate: Digital outputs
are inhibited.
Reaction
The red STOP LEDs on the
CPUs at which the OVERALL
RESET was executed, light up
continuously. Each CPU
additionally emits the output
inhibit signal (BASP LED
continuously lit).
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