Mitsubishi Electric Q Series Reference Manual page 285

7 APPLICATION FUNCTIONS
When executing the instruction, provide an interlock between
SW01FC to SW01FF (redundant system status) for judging
whether the target station is a control system.
7 - 83
(d) Program example 2 (when a redundant system is the target system)
When the target station is in a redundant system, the ZNRD instruction
must be executed after judging whether it is a control system.
The program example shown below is an interlock program for reading D10
to D14 of the control system CPU of the redundant system consisting of
station Nos. 1 and 2 into D200 to D204 of the host station.
Provide the identical interlock for the ZNWR instruction.
The ZNRD instruction is executed to station No. 1
(when station No. 1 is a control system)
The ZNRD instruction is executed to station No. 2
(when station No. 2 is a control system)
MELSEC-Q
7 - 83