Siemens S5-135U/155U User Manual

Page 274

6-12

System Manual

C79000-G8576-C199-06

Setting the coordinator mode switch to RUN or TEST:

IF ...

THEN ...

Reaction

You do not wish to
work in the test mode

Set the coordinator
mode switch from
STOP to RUN.

The green RUN LEDs
of all CPUs are
continuously lit. All
CPUs simultaneously
go into the cycle. The
output inhibit signal is
not emitted (BASP
LED = off).

You wish to work in the
test mode (it must be
enabled on the
coordinator)

Set the coordinator
mode switch from
STOP to TEST.

Test mode and setting: see Section 6.3

Symptom:

All CPUs remain in the Stop state.

Remedy:

Check whether the mode switches of all CPUs are set to RUN.

A subsequent start of individual CPUs is not possible. Switch the coordinator
back to STOP. Execute a RESET at all CPUs and then switch the coordinator
to RUN again.

Note

During the starting phase (processing of the start OBs) the STOP and RUN
LEDs remain off at all CPUs. The RUN LED only lights up continuously
when the CPUs go over to cyclic program processing.

When the coordinator is switched from STOP to TEST, only the CPUs
whose switches are at the RUN setting will operate in the test mode.

If the 923C coordinator is used and the PG interface on the front plate is
not connected to the PG and switched online, the IF FAULT LED lights
up on the 923C coordinator. The indicator can be ignored in this case.

Step 8

Possible Faults

Notes Relating to
Multiprocessor
Start

Multiprocessor Operation/Coordinators