Note the following:
● Only trained service employees should be authorized to work on the process control
● Always observe the plant-specific rules and government regulations when making
● Observe the plant-specific boundary conditions and adjust the work accordingly.
● Always bear in mind that changes in a system can impact other sections of the system.
Information on the affected CPU
The following information is needed when a CPU fault occurs:
● Order number
● Firmware version
● Hardware version
If you can access the CPU from the engineering station, you can query this information via the
module information. For additional information, refer to the "Module information (Page 112)"
A constantly updated list of all module information facilitates troubleshooting in the event of
a fault and reduces the time needed for correcting the fault.
Information in the event of a fault
The following information is needed if a fault occurs:
● Operations and actions/event history leading to the fault
● Status indicated by LED displays on the front of the CPU (such as RUN)
Only the RUN LED is lit
The SIMATIC station is functioning without errors.
RUN LED and additional red LED is lit
Faults have occurred in the SIMATIC station. Use the diagnostic tools for analysis. For
additional information, refer to the "Diagnostics for the CPU (Page 81)" section.
STOP LED is lit
Service support and diagnostics (V8.0)
Service Manual, 03/2012, A5E02779775-02
changes to a system.
Failure - What next?
6.2 Preparing for expert support