Technical data

4.3.2
Requesting an OVERALL
RESET
Request by the system
program
Each time you turn on the power and perform an overall reset, the
CPU runs through an initialization routine. If errors are detected
during this initialization, the CPU changes to the STOP mode and the
STOP LED flashes quickly.
Possible errors: Contents of the RAMs are not correct.
Remedy: overall reset on the CPU
Contents of the user EPROM are not
correct
Remedy: insert programmed EPROM
and overall reset on the CPU
You must deal with the cause of the problem and then perform an
overall reset on the CPU again. OVERALL RESET is also requested
if a CPU or system error occurs. You can recognize this error by the
fact that the request appears again following an OVERALL RESET.
In this case, call your SIEMENS representative.
Operator request You request OVERALL RESET as follows:
1. Switch the mode selector from RUN to STOP.
Result: the CPU is in the STOP mode. The STOP LED is lit
continuously.
2. Hold the momentary-contact mode selector in the OVERALL
RESET position; at the same time, switch the mode selector from
STOP to RUN and back to STOP.
Result: you request an OVERALL RESET. The STOP LED
flashes quickly.
Note
If you do not want the OVERALL RESET that you requested to
be executed, carry out a COLD RESTART or MANUAL WARM
RESTART.
4
STOP Mode
CPU 928B Programming Guide
C79000-B8576-C898-01
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