Mitsubishi Electric MELSEC-Q Series - Redundant-CPU-Compatible Function; Overview of Redundant System Operation

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4.7 Redundant-CPU-Compatible Function
This section explains the case of using the CC-Link IE Controller Network module with Redundant CPUs.
4.7.1 Overview of redundant system operation
(1) Cyclic transmission processing
1. A redundant system is composed of system A and system B, and the same send ranges for
respective stations in link devices (LB/LW) are set for stations of systems A and B.
*1
2. The station acting as the control system sends and receives cyclic data.
3. The station acting as the standby system only receives cyclic data.
4. The source CPU-side-device data in the own station's send range in the link devices (LB/LW) must
be tracking-transferred.
*2*3
For details of tracking transfer, refer to the following.
QnPRHCPU User's Manual (Redundant System)
*1 Pairing is not available for communication using LX/LY.
*2 Tracking transfer is not available for link direct devices (J\).
*3 Do not use tracking transfer for the link special relay (SB0020 to SB01FF) and link special register (SW0020 to
SW01FF) that are turned ON/OFF by the system.
Redundant system
Tracking cable
4. Tracking transfer
Normal station
No.3
Normal station
No.4
Link relay (LB)
LB0
LB7FFF
No.1, 2 send range
No.3
No.4
No.1, 2
No.3 send range
No.4
No.1, 2
No.3
No.4 send range
No.3
No.4
1. 2. 1. 3.
System A
(control system)
Control station
No.1
System B
(standby system)
Normal station
No.2