Mitsubishi Electric Melsec Q Series User Manual page 98

4 WHEN THE Q/LCPU ACCESSES THE PROGRAMMABLE CONTROLLER
OF ANOTHER STATION USING THE DATA LINK INSTRUCTION
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(Example) READ instruction execution timing
1) Communication timing when the READ instruction completed
successfully (when resend is not performed)
Programmable
controller CPU (Local station)
READ
Arrival
monitoring
time (*1)
(Execution
completion)
2) Communication timing when the READ instruction completed
successfully (when resend is performed)
Programmable
controller CPU (Local station)
READ
Arrival
monitoring
time (*1)
(Resend)
Repeat for
the number
of resend.
(*2)
(Execution
completion)
1 The user designates the arrival monitoring time with the READ
instruction control data ((S1)+8).
2 The user designates the number of resend with the READ
instruction control data ((S1)+7).
This item must be set at every instruction execution.
3 The Ethernet module performs a resend of the command for
the number of resend when this response is not received.
4 The receiving side Ethernet module notifies the sending side
Ethernet module of successful data reception.
E71
Command (UDP)
Receive response
(UDP) (*4)
Response
Receive response
(UDP) (*4)
E71
Command (UDP)
Receive response
(UDP) (*4)
No response (*3)
Command (UDP)
Receive response
(UDP) (*4)
Response
Receive response
(UDP) (*4)
MELSEC-Q/L
E71 Programmable
(another station) controller CPU
Read request
Read data
E71 Programmable
(another station) controller CPU
Read request
Read data
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