Maintenance; Replacing Components Of The S7-1500R/H Redundant System; Checking Before Replacing Components - Siemens Simatic S7-1500R System Manual

Maintenance

11.1

Replacing components of the S7-1500R/H redundant system

11.1.1

Checking before replacing components

Introduction
Please observe the following rules if the redundant system is in the RUN-Solo system state:
● Do not immediately start replacing components.
● Do not immediately switch the failed CPU to the RUN. operating state.
First check the pairing status in the RUN-Solo system state.
Checking pairing in the RUN-Solo system state
Do not switch the failed CPU in the RUN-Solo system state to the RUN operating state.
This could result in an undefined system state for the redundant system. Both CPUs would
become primary CPUs.
If the S7-1500R/H redundant system is in the RUN-Solo system state, you must not
immediately switch the backup CPU to the RUN operating state.
Possible cause: No pairing between the two CPUs. Check the pairing status on the display
or on the basis of the diagnostics status or diagnostics buffer.
If there is no pairing, the redundancy connections have been interrupted, for example. In
this case, please note the procedure below.
S7-1500R/H redundant system
System Manual, 10/2018, A5E41814787-AA
CAUTION
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