Mitsubishi Electric MELSEC iQ-R Series User Manual page 51

Redundant line
In redundant line configuration, the control system and standby system of the remote head module are determined by tracking
the master station.
■When the system starts by turning the power on
The control system and standby system are determined by tracking the master station.
• In the interval after the system starts by power-on till the control system and standby system are determined
by tracking the system status of the master station, remote head No.1 will be the control system and remote
head No.2 will be standby system.
• If the remote head modules are not connected with the master station, the control system and the standby
system are determined by tracking the system status of the master station when the modules are connected
with the master station.
• If the files of both systems are mismatch, memory copy operation is performed for remote head No.2
(standby system) from remote head No.1 (control system). After memory copy operation completes, the
control system and the standby system are determined by tracking the system status of the master station.
• When only remote head No.2 is mounted or remote head No.1 has failed, the system does not start. To start
the system, remote head No.1 must be replaced, or remote head No.2 must be mounted in the CPU slot.
■When the system starts by resetting the remote head module of the control system
Only the remote head module of the control system is reset.
The redundant master station system detects a reset of the remote head module of the control system, and systems are
switched.
By tracking the system switching of the redundant master station system, the remote head module of the standby system will
become the control system.
After reset clear, the reset remote head module will be the standby system by tracking the system status of the master station.
• When only remote head No.1 is mounted or remote head No.2 has failed, the entire system is reset. After
reset clear, the reset remote head module will be the control system by tracking the system status of the
master station.
• When remote head No.2 is reset and remote head No.1 has failed, the entire system is reset. However,
after reset clear, the system does not start. To start the system, remote head No.1 must be replaced, or
remote head No.2 must be mounted in the CPU slot.
■When the system starts by resetting the remote head module of the standby system
Only the remote head module of the standby system is reset.
After reset clear, the reset remote head module will be the standby system by tracking the system status of the master station.
• When only remote head No.1 is mounted or remote head No.2 has failed, the entire system is reset. After
reset clear, the reset remote head module will be the standby system by tracking the system status of the
master station.
• When remote head No.2 is reset and remote head No.1 has failed, the entire system is reset. However,
after reset clear, the system does not start. To start the system, remote head No.1 must be replaced, or
remote head No.2 must be mounted in the CPU slot.
1 FUNCTIONS
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1.8 Redundant Function
1