7 - 23 7 - 23
MELSEC-Q
7 APPLICATION FUNCTIONS
(c) Switching of multiplexed remote master station operation
When the multiplexed remote master station has returned to system, it can
be switched to master operation in the following procedure.
1) The multiplexed remote sub-master confirms that the multiplexed
remote master station has returned to the system by checking the link
special relay (SB) status.
2) The multiplexed remote sub-master station switches from master
operation to sub-master operation by operating the link special relay
(SB).
3) The multiplexed remote master station switches to master operation
when the multiplexed remote sub-master station switches to sub-
master operation.
Multiplexed remote
master station
Multiplexed remote
sub-master station
Master operation
Master operation
Sub-master operation
Sub-master operation
Remote I/O station
Remote I/O station Remote I/O station
SB0014 of multiplexed remote sub-master station: ON
Multiplexed remote
master station
Multiplexed remote
sub-master station
Shift of control right
During switching, outputs are held.
Remote I/O station Remote I/O station Remote I/O station
The link special relays used to confirm operating status of multiplexed remote master station
Number Name Description
SB0071 Remote master station baton pass status Indicates the baton pass status of the master station.
OFF : Master station baton pass normal
ON : Master station baton pass abnormal
SB0075 Remote master station cyclic transmission
status
Indicates the cyclic transmission status of the master station.
OFF : Master station cyclic transmission normal
ON : Master station cyclic transmission abnormal