Mitsubishi MELSEC LJ71C24, User Manual

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10 DATA COMMUNICATION USING THE NONPROCEDURAL PROTOCOL
Data received prior to an error occurrence will be
stored in the receive data storage device.
For normal completion
(1)
(0)
(n)
(10)
(1)
(other than 0)
(n)
(10)
C24
D 0
D 1
D 2
D 3
D10
D m
Interface number
Reception result
Receive data count
Allowable receive data count
Receive data
Receive data
For abnormal completion
D 0
D 1
D 2
D 3
D10
D x
Interface number
Reception result
Receive data count
Allowable receive data count
Receive data
Receive data
Buffer memory
Data reception result
Receive data count
Receive data
Address
258
H
600
H
601
H
7FF
H
When the receive data count is larger than the
allowable receive data count, only the data up to
the allowable receive data count will be stored
and the excess data will be discarded.
From the buffer memory (address 258
H
)
From the buffer memory (address 600
H
)
to to
to
to to
POINT
(1) Receive data can also be read using interrupt programs.
For 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 INPUT instruction cannot be executed simultaneously.
Execute the next INPUT instruction only after the execution of the first INPUT
instruction is completed.
(4) When the communication data count is set in word units, and if the received
data count is an odd byte when requesting the reading of received data to the
CPU module, the receive data count is processed as follows:
Receive data count = Receive data byte count/2 …Fractions following the
decimal point are rounded up
Also, 00
H
is stored in the higher byte of the final data storage position in the
receive area where receive data is stored.