Mitsubishi Electric MELSEC Q Series Reference Manual page 366

• When the own station is on a redundant system
If a system switching occurs during instruction execution, execution of the instruction is stopped and its
processing is not completed.
To re-execute such an uncompleted instruction in the new control system after system switching, provide
an interlock using One scan ON after system switching (SM1518) and Completion device.
Note that the same instruction may be executed twice.
364
Processing program for write completion
Processing program for normal completion
Processing program for error completion
Control data setting
for WRITE instruction
Stores write data in
D750 to D753.
Set when system
switching occurs during
instruction execution
Execution of WRITE
instruction
Error code reading, etc.
Upon completion
of instruction
execution,
resets M112
to M114.