Mitsubishi Electric MELSEC iQ-R Series - Page 172

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11 BASIC CONCEPT OF REDUNDANT SYSTEM
11.6 System Determination
■Operation
1. Both systems are temporarily powered
off due to a power failure or other
causes while the system B is operating
as the control system.
2. When both systems are powered on,
the system A starts up as the control
system. SM1636 turns on for only one
scan after the operating status of the
CPU module has changed to RUN.
3. The systems are switched by the
SP.CONTSW instruction.
4. The system B is switched from the
standby system to the control system.
System A
Standby system → Power-off
System B
Control system → Power-off
SP.CONTSW K1 M100
SET SM1646
SP.CONTSW K1 M100
SET SM1646
GOEND GOEND
System A
Power-on → Control system
System B
Power-on → Standby system
SystemBrestartflag SystemBrestartflag
System A
Control system
System B
Standby system
System switching
System A
Control system → Standby system
System B
Standby system → Control system