Mitsubishi MELSEC-A Series Reference Manual page 177

7. DATA LINK SETTINGS
(2) Assignment of link registers (W)
(a) Assignment for the master station and local stations (M/L area)
256 points to the master station, 128 points to local station No.2, and 196 points
to local station No.3 are assigned
(b) Assignment for the remote I/O stations (M
Assign 16 points for the RTOP instruction and 16 points for the RFRP instruction
in the user program of the master station as remote I/O station No.1.
No.1 requires 17 points (16 points (for RTOP) + 1 point (for OS)) for the M
area because one special function module is installed.
Assign 32 points for the RTOP instruction and 32 points for the RFRP instruction
in the user program of the master station for the remote I/O station No.4. For
No.4, 34 points (32 points for RTOP + 2 points for OS) are required for the M
R area, because two special function modules are installed.
Fig 7.18 Link register (W) assignment example
(c) The empty area marked with *1 in the M/L area in Fig 7.18 cannot be used as a
substitute for data register (D) in the master station and all local stations.
In addition, empty area of M
register (D) by the master station.
R area marked with *2 cannot be used as a data
7 - 39
R area, M R area)
R