Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 85

3 SPECIFICATIONS
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(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
1M 1
P
1M 1
P
Link data
1M 1
P
1N 2
S
1N 3
S
Communication
error station
Cable disconnection
1N 3
S
Cable disconnection
Link data status after disconnection
1N 2
S
Link data
1M 1
P
1N 2
S
1N 3
S
· · · · · · Area where the link data is retained
MELSEC-Q
2 due to cable disconnection
S
1N 2
S
1N 3
S
Link data
1M 1
P
1N 2
S
1N 3
S
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