System Switching Operation - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

System switching operation

In a redundant system, if the control system fails, the control system and the standby system are switched. For Ethernet, after
system switching, the connection destination is changed to the Ethernet-equipped module of the new control system to
continue the communication with the external device.
The following shows system switching operation when a communication error occurs in the control system.
(1)
1.
A communication error occurs in control system (1).
2.
The RJ71EN71 of control system (1) issues a system switching request to the CPU module.
3.
System switching occurs in the redundant system.
4.
Standby system (2) starts operating as the new control system to continue network control.
For OPS connection, through establishing a TCP/IP connection with both systems, communication can be
smoothly continued simply by changing the communication destination even when system switching occurs.
1 FUNCTIONS
220
1.17 Redundant System Function
(2)