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6 DEDICATED INSTRUCTIONS
[Operation of the local station when the REQ instruction is being executed]
Sequence program
REQ instruction
Send/receive
instruction flag
Completion device
Status display device at
completion
Errors
6 - 30
(4) Whether the REQ instruction is being executed or has been completed normally
or abnormally can be checked with the complete device (D2) or completion status
display flag ((D2) + 1) designated in the set data.
(a) Completion device (D2)
Turns on at the END processing of the scan where the REQ instruction is
completed, and turns off at the next END processing.
(b) Status display device at completion ((D2) + 1)
Turns on and off depending on the completion status of the REQ instruction.
Normal completion: Stays off and does not change.
Abnormal completion: Turns on at the END processing of the scan where
END
END
processing
processing
ON
OFF
ON
OFF
OFF
OFF
(5) When the instruction is executed using J.REQ/G.REQ, the next write processing
is executed in succession after one write processing is completed while the write
command is on.
When the instruction is executed using JP.REQ/GP.REQ, the write processing is
executed only once when the write command switches from off to on (at rise).
(1) When a dedicated instruction completes abnormally, the abnormal completion signal
(D2) + 1 turns on and the error code is stored in the completion status (S1) + 1.
See the following manuals regarding the error code, check the errors and take
corrective actions.
<Error codes>
4FFF
or less : QCPU (Q Mode) User's Manual (Hardware Design,
H
C000
or higher: Section 11.3.3 of the Q Corresponding Ethernet Interface
H
the REQ instruction is completed, and turns off at
the next END processing.
REQ instruction
execution is completed
Maintenance and Inspection)
Module User's Manual (Basic)
MELSEC-Q
END
END
processing
processing
ON
Abnormal
ON
completion
Normal
completion
One scan
6 - 30
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