Automatic Return Function - Mitsubishi Electric MELSEC Q Series Reference Manual

3 SPECIFICATIONS
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(3) Automatic return function

When a station disconnected from a network due to a data link error recovers
from the error, the station is automatically reconnected to the network and
restarts data link.
(a) When a remote I/O station restarts data link (the "D.LINK" LED is lit.)
The remote I/O station resets all of the modules mounted on the station.
If data link is resumed by connecting/disconnecting the link cable, the
modules are not reset.
(b) When parameter change or reset of a remote I/O station (including power
cycle) was performed
After parameters of a remote I/O station are changed, if parameter change
or reset is performed at the remote master station, or if the remote I/O
station is reset (power off and then on, or the reset switch turned on), the
modules will be reset when the remote I/O station returns to the system to
resume the data link. Consequently, even if the output setting under a CPU
error is set to HOLD (retention) in an output module, digital-analog
converter module, or temperature control module, output cannot be
retained when data link is resumed.
1) The remote I/O station No. 2 is disconnected
due to a data link error.
Remote
Remote I/O
master
station
station
(station
(station
No. 1)
No. 0)
Network No. 1
Remote I/O Remote I/O
station station
(station (station
No. 5) No. 4)
POINT
There is a limit to the number of faulty stations that can return to the system within
one link scan. For details, refer to Section 5.1.4, "Supplementary Settings."
Down
Remote I/O
station
(station
No. 2)
Return
Remote I/O
station
(station
No. 3)
MELSEC-Q
2) The station No. 2 recovers to the normal
status and returns to the system.
Remote
Remote I/O
master
station
station
(station
(station
No. 1)
No. 0)
Network No. 1
Remote I/O Remote I/O
station station
(station (station
No. 5) No. 4)
Return
Remote I/O
station
(station
No. 2)
Remote I/O
station
(station
No. 3)
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