Maintenance
14.1 Replacing components of the S7-1500R/H redundant system
14.1.3.3
Replacing defective synchronization module with S7-1500H
Initial situation
A synchronization module has failed.
The redundant S7-1500H is in the RUN-Redundant system state.
Procedure: Replacing the synchronization module
Proceed as follows to replace a defective synchronization module:
1. Check the LEDs X3/X4 (CPU 1517H-3 PN) or LEDs X4/X5 (CPU 1518HF-4 PN) on the primary
and backup CPU. Locate the defective synchronization module on the basis of which LEDs
are off.
2. Replace the defective synchronization module. Connect the redundancy connection (fiber-
optic cable).
3. If the X3/X4 or X4/X5 LEDs remain off, replace the synchronization module on the other
CPU.
Result
The defective synchronization module has been replaced. The X3/X4 or X4/X5 LEDs flicker
yellow/green.
14.1.3.4
Replacing both defective redundancy connections with S7-1500H
Initial situation: Failure of both redundancy connections, one after the other
The two redundancy connections (fiber-optic cables) have been interrupted one after the
other (> 55 ms apart).
The S7-1500H redundant system is in the RUN-Solo system state.
Requirement
Read the information in the section Checking before replacing components (Page 443).
Procedure: Replacing both redundancy connections
Proceed as follows to replace the defective redundancy connections:
1. Check the LEDs X3/X4 (CPU 1517H-3 PN) or LEDs X4/X5 (CPU 1518HF-4 PN) on the primary
and backup CPU. If all LEDs are off, both redundancy connections are defective.
2. Replace the redundancy connections (fiber-optic cables) one after the other.
3. Start the CPU which is in STOP mode.
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S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF