MITSUBISHI ELECTRIC QJ71C24N - Manual (Page 233)

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MELSEC-Q
9 DEDICATED INSTRUCTIONS
Function
(1) Data stored in the device designated in (S2) and succeeding devices are sent
according to the control data of the device designated in (S1) and succeeding
devices, via the on-demand function of the MC protocol of the module designated in
Un.
(S2)+ 0
+ 1
+ 2
b15 b0 to
Channel 1
Channel 2
QCPU Q series C24
Send
Send
Channel to be
used is set by
the control data.
(2) When an ONDEMAND instruction is executed on a channel, other ONDEMAND
instructions cannot be executed on that channel at the same time.
If an attempt is made during execution of an ONDEMAND instruction to execute
another ONDEMAND instruction, the second instruction will not be executed until
the execution of the first instruction is completed.
(3) Whether an ONDEMAND instruction was completed normally or abnormally can
be checked by the completion device ((D)) or status display device at completion
((D)+1).
(a) Completion device : Turns on at the END processing of the scan where
the ONDEMAND instruction is completed, and turns
off at the next END processing.
(b) Status display device
at completion : Turns on and off depending on the completion status
of the ONDEMAND instruction.
• Normal completion : Off with no change.
• Abnormal completion: Turns on at the END
processing of the scan where
the ONDEMAND instruction
is completed, and turns off at
the next END processing.
[Operation during execution of an ONDEMAND instruction]
Sequence
program
ONDEMAND
instruction
Completion device
Status display device
at completion
END
processing END
processing
Execution of ONDEMAND
instruction
Completion of reading user frame
by ONDEMAND instruction
ON
ON
Abnormal
completion
Normal
completion
One scan
OFF
OFF
END
processing END
processing