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MELSEC-Q
4 WHEN THE QCPU ACCESSES THE OTHER STATION PLC USING THE
DATA LINK INSTRUCTION
(b) When abnormal completion
1) SEND instruction
Channel 1
Data
sending
0
END
Sequence scan
0
END
0
END
0
END
0
END
Send command
SEND
?
Error code
Send completion device
(Device designated with (D))
Sending side
Q/QnACPU
Send completion device
((D)+1 device )
Ethernet
module
Completion status
((S1)+1 device)
1 scan
Send error
Resend (when designated for twice)
Data
sending
Data
sending
2) RECV instruction
Channel 3
0
END
Sequence scan
0
END
0
END
0
END
RECV
0
END
0
1 scan
?
Error code
Ethernet
module
Receiving side
Q/QnACPU
Receive completion device
((D2)+1 device)
Receive completion device
(Device designated with (D2))
Arrival time over
Completion status
((S)+1 device)
RECV instruction
execution request flag
(
1)
1 The RECV instruction execution request flag for Channel 3 used at the receiving
side Q/QnACPU is as shown below.
For Ethernet module : Bit 2 of the RECV instruction execution request area
(address: 205) in the buffer memory
For the N/W module : SBA2 of the link special relay
