Installing updates and service packs
3.3 Checking plant status
3.3.10
Process control messages
Process control messages are error messages caused, for example, by the failure of a
component or a wire break affecting a connected I/O signal.
Process control messages of the "System, need not be acknowledged" message class are
intended for maintenance personnel. It is the responsibility of maintenance personnel to view
the process control list regularly and resolve any problems that occur.
Note
You can find a list of system messages and a general definition of the measures that need to
be taken in the FAQ "What are the causes of PCS 7 control technology and system
messages and what measures are to be taken to clear them?"
(https://support.industry.siemens.com/cs/ww/de/view/37696303).
Scenario
A redundant OS server needs to be serviced. The standby server has lost the connection to
the AS. If the master server is deactivated in this situation, the plant can no longer be
operator-controlled because the standby server has not established process communication.
To avoid this situation, you need to check the process control message list before
deactivating an OS server and resolve the causes of critical messages that are still relevant.
It helps here to filter the process control list for the name of the computer you want to
service.
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Compendium Part D - Operation and Maintenance (V9.0)
Operating Manual, 02/2018, A5E43228948-AA