Mitsubishi Electric MELSEC iQ-R-R00CPU, User Manual

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26 BASIC CONCEPT
26.8 State Transition of the Redundant System
26.8
State Transition of the Redundant System
The following figure shows the state transition due to the operation mode change and system switching for the redundant
system after start-up.
(1) When both systems are powered off, both systems enter the power-off state regardless of the operation mode or system type.
(2) When a system that has been powered is started as the control system. (

Page 411 When starting up one system first)
System A: Standby system
System B: Control system
Separate mode
System A: Control system
System B: Off
System A: Off
System B: Control system
System A: Control system
System B: Standby system
System A: Standby system
System B: Off
System A: Off
System B: Standby system
System A: Off
System B: Off
Backup mode
System A: Off
System B: Control system
System A: Control system
System B: Standby system
System A: Standby system
System B: Control system
Power off the
system A.
(System switching)
Operation mode change Operation mode change
System A: Control system
System B: Off
Power off the system B.
(System switching)
Both systems: Powered off (1)
Power off the system A. Power on the system A. System switching
System switching
Power off the
system A.
Power on the
system A.
Power off the
system B.
Power on the
system B.
Power off the
system B.
Power on the system A. (2) Power on the system B. (2) Power on the both systems.
Power off the
system A.
Power on the
system A.
Power off the
system B.
Power on the
system B.
Power on the
system B.