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

Maintenance

13.1

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

13.1.1

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.
Observe the following procedure.
Checking pairing state
You have the following options for checking the pairing state:
• Directly from the display of the backup CPU.
In the "Overview > Redundancy > Pairing state" menu:
– Paired
– Single paired (X*P*)
– Not paired
– Not paired - Too many partners
– Not paired - Article number mismatch
– Not paired - Firmware mismatch
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
CAUTION
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