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30 MAINTENANCE AND INSPECTION FOR A REDUNDANT SYSTEM
30.1 Module Replacement in the Redundant System
When the automatic memory copy function is disabled
1. Check the system of the replacement target CPU module.
Check the CTRL LED and SBY LED of the redundant function module in the system of the replacement target CPU module
for the following. The target module is in the standby system in this case.
• The CTRL LED is off and the SBY LED flashes on the redundant function module of the system of the replacement target
CPU module.
2. Power off the standby system.
Power off the standby system. When the standby system is powered off, the BACKUP LED of the redundant function module
in the control system flashes. (The control system will wait for the start-up of the other system.)
3. Replace the CPU module in the standby system.
Replace the CPU module in the standby system with a new CPU module whose model is the same as that of the CPU module
in the control system. If an SD memory card or an extended SRAM cassette has been inserted to the replacement target CPU
module, insert it to the new CPU module.
4. Change the switch status of the CPU module in the standby system.
Set the RUN/STOP/RESET switch of the CPU module in the standby system to the RUN position.
5. Power on the standby system.
Power on the standby system.
6. Memory copy from control system to standby system
The memory is copied with the engineering tool or the special relay and special register. ( Page 471 Memory copy with
the engineering tool, Page 472 Memory copy with the special relay and special register)
When the memory copy is completed, the MEMORY COPY LED of the redundant function module in the control system turns
off and that in the standby system turns on.
7. Restart the standby system.
Restart the standby system. When the standby system is powered on, the BACKUP LED of the redundant function module in
the control system turns on. (The control system will not wait for the start-up of the other system.)
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