Mitsubishi MELSEC LJ71C24, User Manual

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11 DATA COMMUNICATION USING THE BIDIRECTIONAL PROTOCOL
Interface number
Reception result
Receive data count
Allowable receive data count
Receive data
Receive data
D 0
D 1
D 2
D 3
D10
D m
When the received data count is larger than the
allowable received data count, only the data up to
the allowable received data count will be stored
and the excess data will be discarded.
Buffer memory
Data reception result
Receive data count
Receive data
Address
258
H
600
H
601
H
7FF
H
For normal completion
(1)
(0)
(n)
(10)
C24
to
to
to
POINT
(1) Receive data can also be read using interrupt programs.
For more details on reading receive data with interrupt programs, refer to the
User's Manual (Application).
Note that if the reading of data received from the same interface is to be
performed, it is not possible to combine the reading of data received by the
main program and reading of data received by the interrupt program.
Accordingly, either of the above program to read the data received.
(2) The SPBUSY instruction is used to read the execution status when using a
dedicated instruction. (Refer to Chapter 12.)
(3) More than one BIDIN instruction cannot be executed simultaneously.
Execute the next BIDIN instruction only after the execution of the first BIDIN
instruction is completed.
(4) If the communication data count is set in byte units and the receive data count
is an odd byte when requesting the reading of receive data to the CPU
module, 00
H
is stored in the higher byte of the final data storage position in the
receive data storage area.