Mitsubishi Electric MELSEC iQ-R Series User Manual page 172

■Operation
System A
Standby system → Power-off
System A
Power-on → Control system
SystemBrestartflag
SET SM1646
SP.CONTSW K1 M100
GOEND
System A
Control system
System A
Control system → Standby system
11 BASIC CONCEPT OF REDUNDANT SYSTEM
170
11.6 System Determination
System B
Control system → Power-off
System B
Power-on → Standby system
SystemBrestartflag
SET SM1646
SP.CONTSW K1 M100
GOEND
System B
Standby system
System switching
System B
Standby system → Control system
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.