Mitsubishi Electric MELSEC iQ-R Series User Manual page 436

Re-execution of instruction when systems are switched during instruction execution
When the system switching is performed while an instruction that requires several scans is being executed, the instruction can
be executed again in the new control system after the system switching by using the programs such as following.
■REMFR instruction
When the system switching is performed while the instruction is being executed (M201 = ON), SM1643 (ON for only one scan
after system switching (standby system to control system)) will turn on for one scan in the new control system and the REMFR
instruction will be executed again on station number 10 of network number 1.
• Devices used
Device
SM1643
*1
SB47
*1
SW0A0.9
*2
M200
*2
M201
*2
M202
*2
M203
*2
M204
*1 For details on the link special relay (SB) and link special register (SW), refer to the manuals for the network used.
*2 Change the device number according to the system.
• Program example
26 REDUNDANT FUNCTION
434
26.11 Precautions on Programming
Description
ON for only one scan after system switching (standby system to control
system)
Baton pass status of own station
Baton pass status of each station
Reading request
At instruction execution
ON at instruction re-execution request due to system switching
Completed without an error
Completed with an error