Mitsubishi MELSEC-A Series Reference Manual page 174

7. DATA LINK SETTINGS
(3)
(4)
Assign the input (X) and output (Y) range used for data link to the I/O number used in
the I/O module and special function module by the master station I/O. (Refer to
Section 7.6.4)
(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 the range.
(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.................
• Local station...................
• Remote I/O station.........
POINT
(1) If the M R area used by the system is used incorrectly in a user program,
data cannot be read/written correctly, when the RFRP/RTOP instruction is
executed.
(2) The number of link points can be reduced by mounting modules to a remote
I/O station in groups of input modules, special function modules, and output
modules as shown below. If the installation of I/O modules is changed from (a)
to (b), a reduction of 16 input assignment points and 32 output assignment
points can be achieved.
1024 bytes or less
1024 bytes or less
512 bytes or less
(Inputs and outputs is 512 points or less of X/Y0 to
1FF)
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