User's Manual
4. HOW TO MONITOR REDUNTANT SYSTEM
4.4 CC-Link Connection (Via G4)
4 - 21
1
PREPARATORY 
PROCEDURES FOR 
MONITORING
2
DEVICE RANGE 
THAT CAN BE SET
3
ACCESS RANGE 
FOR MONITORING
4
HOW TO MONITOR 
REDUNTANT 
SYSTEM
5
BUS CONNECTION
6
DIRECT 
CONNECTION TO 
CPU
7
COMPUTER LINK 
CONNECTION
8
ETHERNET 
CONNECTION
(3) Monitoring target change when system switching occurs in a redundant system
(a) System switching due to an alarm occurred in the control system
When system switching occurs, the CC-Link switches the station No. 0 of the master station and the station 
No. 1 of the standby master station on the network.
The CC-Link module of the new control system after system switching takes over the control as the master 
station.
Since the GOT monitors the master station, the monitoring target is automatically changed to the new 
control system after system switching.
(b) System switching due to a network communication error occurred in other than the CC-Link of the control 
system, or due to switching by the user
When system switching occurs, the CC-Link does not switch the station No. 0 of the master station and the 
station No. 1 of the standby master station on the network.
The CC-Link module of the new control system after system switching takes over the control as the 
standby master station.
Since the GOT monitors the master station, the monitoring target is not automatically changed to the new 
control system after system switching.
To automatically change the monitoring target of the GOT to the new control system after system switching, 
switch the data link control from the standby master station to the master station by the sequence program 
of the new control system.
For details of the sequence program, refer to the following manual.
QnPRHCPU User's Manual (Redundant System)
(Sample Programs when Using CC-Link)
POINTPOINTPOINT
CC-Link network setting
To automatically change the monitoring target in the QCPU redundant system when using the CC-Link connection, 
set the CC-Link master station as System A and the standby master station as System B.
For details of using the CC-Link network in the redundant system, refer to the following manual.
CC-Link System Master/Local Module User's Manual
QnPRHCPU User's Manual (Redundant System)










