Mitsubishi Electric MELSEC iQ-R Series - State Transition of a Redundant System

11 BASIC CONCEPT OF REDUNDANT SYSTEM
11.7 State Transition of a Redundant System
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11.7 State Transition of a Redundant System
The following figure shows the state transition of a redundant system after start-up based on the operation mode change and
system switching.
(1) When both systems are powered off, both systems transition to the power-off state regardless of the operation mode or system type.
(2) A system that is powered on starts up as the control system. ( Page 163 When only one system is started up)
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.