Mitsubishi Electric Q80BD-J71BR11, Руководство пользователя

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MELSEC
4 FUNCTION
(2) Link scan and link refresh
The link scan is executed "asynchronous" with the sequence scan of the CPU
module.
The link refresh is executed by the "END processing" of the CPU module.
END 0 Sequence scan
Link scan
END 0 END 0 END 0
Link refresh Link refresh Link refresh
(3) Link data when a communication error station or communication
stop station occurs on the network
When a communication error or communication stop station occur on the network
during the data link, the receive data from those stations immediately before the
error occurrence is retained.
(A "communication stop station" refers to a station whose cyclic transmission has
been stopped by a peripheral device.)
(a) The receive data from a communication error station or communication stop
station is retained by a normally communicating station.
(b) The receive data from other station is retained by a communication stop
station.
(Example)
When a communication error has occurred to 1N
S
2 due to cable disconnection
1N
S
3
1M
P
1 1N
S
2
Cable disconnection
Communication
error station
1M
P
1
1N
S
2
1N
S
3
1N
S
2
1M
P
1
1N
S
2
1N
S
3
1M
P
1
1N
S
2
1N
S
3
· · · · · · Area where the link data is retained
1M
P
1 1N
S
3
Link data status after disconnection
Link data Link data Link data
Cable disconnection