Mitsubishi Electric MELSEC Q Series Reference Manual page 142

(3) Pairing settings for the redundant system
When a network contains a redundant system, pairing settings are required for network parameters of the control
*1
station.
Configure the setting in "Pairing" of "Network Range Assignment" of the control station. (
6.3.4)
*1 Check the serial No. and software version for applicability. (
(4) Project file in a programming tool
For a redundant system, create parameters and programs in one project file and write them to programmable
controllers of both systems.
(5) Precautions
(a) When the redundant system is in the debug mode
Do not connect the CC-Link IE Controller Network modules on both systems to the network at the same time.
In the debug mode, system B CPU also operates with the same parameters as system A. Therefore,
duplication of the control station and station number is detected at the time of concurrent connection to the
network.
(b) Error detection due to power ON/OFF of another station (including the standby
system)
A system switching request may be issued due to detection of a temporary data link error in the following
cases:
• Power ON/OFF of another station (including the standby system)
• Boot or shutdown of a personal computer with a CC-Link IE Controller Network interface board
If the above system switching request is issued before startup of the standby system, a continue error, "CAN'T
SWITCH" may be detected in the control system CPU.
Since normal control can be continued even if "CAN'T SWITCH" is detected, program the system properly so
that this error detection will not stop the control.
For information on how to clear "CAN'T SWITCH", refer to the following.
QnPRHCPU User's Manual (Redundant System)
140
Page 606, Appendix 3)
Page 199, Section