Siemens Simatic S7-1500H - Page 326

Requirement
Read the information in the section Checking before replacing components (Page 319).
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.
Result
The defective redundancy connections have been replaced. The redundant system switches
to the RUN-Redundant system state. The X3/X4 or X4/X5 LEDs flicker yellow/green.
Initial situation: Failure of both redundancy connections simultaneously
The two redundancy connections (fiber-optic cables) have been interrupted simultaneously
(≤55ms apart).
Both H-CPUs are primary CPUs. The S7‑1500H redundant system is in an undefined system
state.
Procedure: Replacing both redundancy connections
Proceed as follows to replace the defective redundancy connections:
1.
Immediately switch an H-CPU to the STOP operating state.
2.
Replace the redundancy connections (fiber-optic cables) one after the other.
3.
Switch the H-CPUs back to the RUN operating state.
Result
The redundant system switches to the RUN-Redundant system state. The X3/X4 or X4/X5 LEDs
flicker yellow/green.
326
S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD
Maintenance
13.1 Replacing components of the S7-1500R/H redundant system