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6.2 Redundant System Network Overview
6.2.4 CC-Link
6
(b) When System Switching Occurs due to Communication Error in Network
other than CC-Link
When a communication error occurs in a network other than CC-Link, system
switching occurs and the new control system takes over the control of the
redundant system.
However, the new standby system master station does not switch to the standby
master station, as it can communicate with remote stations.
Also, the new control system standby master station remains as the standby
master station, and cannot control remote stations as the master station.
As a result, the new control system is unable to control the CC-Link.
Make sure to switch the data link control from the standby master station to the
master station using the new control system's program.
Refer to Appendix 4 for program details.
Diagram 6.27 Operation at System Switching due to Communication Error of Network other
than CC-Link
Master Station
(Station No. 0)
Standby Station
(Station No. 1)
Master Station
(Station No. 0)
Standby Station
(Station No. 1)
CC-Link
Remote I/O station
(station No. 2)
CC-Link
Remote I/O station
(station No. 2)
System A -
Control System
System B -
Standby
Communication
not possible
System A -
Control System
System B -
Standby System
MELSECNET/H PLC to PLC network
MELSECNET/H PLC to PLC network
Station number used for the network
Station number used for the network
Tracking cable
Tracking cable