Mitsubishi QJ71C24N User Manual page 302

10 DEDICATED INSTRUCTIONS
Error
Program example
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(3) Whether a BIDIN instruction was completed normally can be checked by the
completion device ((D2)) or status display device at completion ((D2)+1).
(a) Completion device: Turns on at the END processing of the scan where the
(b) Status display device at completion: Does not change when left off.
[Operation during execution of a BIDIN instruction]
Sequence
program
BIDIN
instruction
Completion device
Status display device
at completion
(1) In case of operation errors, the error flag (SM0) turns on and the error code is
stored in SD0.
See one of the following manuals according to the error code, and check and
correct the error.
<Error code>
4FFF or less : QCPU User's Manual
H
(Hardware Design, Maintenance and Inspection)
The following example shows a program that receives any data using the bidirectional
protocol and stores that data in D10 or later.
The input/output signals of the Q series C24 are from X/Y00 to X/Y1F:
BIDIN instruction is completed normally, and turns off at
the next END processing.
END
END
processing
processing
Execution of BIDIN instruction
OFF
OFF
MELSEC-Q
END
processing
Completion of reception by
BIDIN instruction
ON
One scan
Designate the receive channel.
Clear the receive data count storage device to 0.
Designate the allowable receive data count.
With the normal completion, the receive data within
the allowable receive data count (user designated)
is read from the receive data storage area in the
buffer memory.
After the BIDIN instruction is executed, the user
•
designated read completion signal (M0) comes
on for 1 scan.
The reading of received data is performed by the
•
programmable controller CPU.
END
processing
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