Mitsubishi Electric MELSEC iQ-R Series, Programming Manual

Page: 1447 / 2110

14 REDUNDANT SYSTEM INSTRUCTIONS
14.2 Disabling/Enabling System Switching
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Ex.
When the SP.CONTSW instruction is executed while the system switching operation is disabled by the DCONTSW instruction
• The following operations enables system switching. To disable system switching, execute the DCONTSW instruction again.
Operation error
There is no operation error.
• Powering off and on the standby system
• Resetting the CPU module in the standby system
• Changing the operating status of the CPU module in the standby system from RUN to STOP
• A stop error in the CPU module of the standby system
• Switching the operation mode from backup mode to separate mode
• Automatic system switching
END
END
END
END
System A
System B
Program executed Program executed
Control system
SP.CONTSW instruction
Standby system
Execution of the instruction
System switching
disabled
System switching disabled section
Program executed
Execution of the instruction
DCONTSW instruction
(System switching prohibited)
ECONTSW instruction
(System switching enabled)
Execution of the instruction
Program executed