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MELSEC-Q
6 DEDICATED INSTRUCTIONS
(2) The instructions for Ethernet module cannot be executed to two or more locations
for the same channel.
If the execution conditions are met at two or more locations at the same time,
instructions to be executed later have to wait until the channel becomes available
because handshaking is automatically performed at the execution of the first
instruction.
(3) RECVS instruction (for interrupt program) cannot be used with the instruction for
data link in cases where the same channel is used to read receive data using the
instruction for data link.
(4) Whether the RECV instruction is being executed or has been completed normally
or abnormally can be checked with the completion 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 RECV 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 RECV instruction.
Normal completion: Stays off and does not change.
Abnormal completion: Turns on at the END processing of the scan where
the RECV instruction is completed, and turns off at
the next END processing.
[Operation of the local station when the RECV instruction is being executed]
Sequence program
RECV instruction
OFF
ON
RECV instruction
execution is completed
END
processing
RECV instruction
execution request
(buffer memory
address: 205)
OFF
ON
Completion device (D2)
Status display device
at completion (D2) + 1
Abnormal
completion
Normal
completion
One scan
OFF
OFF
ON
ON
END
processing
END
processing
END
processing
(5) When executing the instruction using JP.RECV/GP.RECV, the read processing is
executed only once when the read instruction flag goes from off to on (at rise).
Errors
(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 (S)+1.
See the following manuals regarding the error code, check the errors and take
corrective actions.
<Error codes>
4FFF
H
or less
: QCPU (Q Mode) User's Manual (Hardware Design,
Maintenance and Inspection)
C000
H
or higher: Section 11.3.3 of the Q Corresponding Ethernet Interface
Module User's manual (Basic)
