Mitsubishi MELSEC Q Series Programming Manual page 543

[Timing Chart]
Y30 to Y37
OFF
PRC
Y38
OFF
(Strobe signal)
Y39
OFF
(Flag indicating strobe
signal is being output)
SM721
OFF
(File access in
progress flag)
SM720
OFF
(File access
completion flag)
(2) Output signals from the output module are transmitted at the rate of 30 ms per character.
For this reason, the time required to the completion of the transmission of the designated
number of characters will be 30 ms
At 10ms interrupt intervals, the PRC instruction executes data output, strobe signal ON, and
strobe signal OFF. The other instructions are executed continuously during a period
between the above processings.
Data output
OFF
Strobe signal
(3) In addition to the ASCII code, the output module also outputs a strobe signal (10 ms ON, 20
ms OFF) from the
D
(4) Following the execution of the PRC instruction, the PRC instruction execution flag (
device) remains ON until the completion of the transmission of the designated number of
characters.
(5) The PRC instruction can be used multiple times, but it is preferable to establish an interlock
with the PRC instruction execution flag (
simultaneously.
(6) If no comments have been registered at the device designated by
performed.
(7) When a comment is read, SM720 turns ON for one scan after the instruction is completed.
SM721 turns ON during the execution of the instruction.
The PRC instruction cannot be executed while SM721 is ON. If the attempt is made, no
processing is performed.
A
Preprocessing 41
H
(several scans)
30 ms
ON
ON
10 10 10
ms ms ms
ON
ON
PRC instruction cannot be executed again.
ON
None of Instructions other than PRC instruction (SP.FREAD,
instructions can SP.FWRITE, PUNROAD, PLOAD, PSWAPP) can be executed.
be executed.
n (ms).
Execution of sequence program
ON
10 ms
10 ms 10 ms
30 ms
+ 8 device.
+ 9 device) so that they will not be ON
D
B C
42 43
H H
30ms x 16 = 480 ms
Processing of PRC instruction
10 ms 10 ms
, processing will not be
S
PRC
1
n O
4E 4F
H H
2
3
4
6
6
7
8
+ 9
D
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