Mitsubishi MELSEC-A Series Reference Manual page 192

7. DATA LINK SETTINGS
(5)
(6)
(b) Consider the range used by the system when assigning the M
The system uses the M
1) Number of points used by the system
The link register (W) 1 point is used for one special function module installed
to a remote I/O station.
2) Range used by the system
The range used by the system is from the head device number of M
area assigned to each remote I/O station to "number of use points - 1 ".
For example, when two special function modules are installed to remote I/O
station No.3, the range W380 to 381 in the M
by the system as shown below.
Assign the input (X) and output (Y) range used for data link to the I/O number used by
the master station as I/O of host station.
(a) Divide the area used for data link into an M/R area (for communication between
the master station and a remote I/O station) and an M/L area (for communication
between the master station and a local station) to assign.
(b) The M/L area is used when the number of link relay (B) points is insufficient.
Therefore, it is not necessary to assign the M/L area when there is sufficient
number of link relay (B) points.
Make sure that the number of link points per station is as follows. (Refer to Section
7.6.1.)
• Master station first half link parameters......... 1024 bytes or less
• Master station second half link parameters... 1024 bytes or less
• Local station first half link parameters........... 1024 bytes or less
• Local station second half link parameters..... 1024 bytes or less
• Remote I/O stations....................................... 512 bytes or less
R area to execute the RFRP/RTOP instructions.
(Inputs and outputs are 512 points
of X/Y0 to 1FF)
7 - 54
R area.
R area W380 to 3BF is used
R