System Switching Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

System switching function

This section describes how to switch systems when a redundant system is operating, whether or not the system switching can
be executed, operations after the cause of failure to switch systems is eliminated, and how to check information on system
switching.
For calculation method of the time required for system switching, refer to the following.
Page 166 System switching time
System switching method
Two types of system switching of the remote head module are available: Automatic system switching (switching automatically
performed by the redundant system) and manual system switching (switching that can be arbitrarily performed).
Line type System System switching cause
switching
method
Single line Automatic Reset or hardware failure
system switching
Moderate error or major error
Data link error
Manual system System switching operation using the engineering tool
switching
Redundant Automatic Tracking of system switching of redundant master station system
line system switching
When multiple simultaneous system switching requests occur, system switching is performed in descending order of priority of
switching causes.
In single line
■System switching due to reset or hardware failure
If the remote head module of the control system is in any of the following state and the redundant system goes out of control,
the remote head module of the standby system switches to the control system to continue the control of the redundant
system.
• The remote head module is reset.
• Hardware failure has occurred
(1)
(4)
(2) (3)
(1) Master station
(2) Control system  New standby system
(3) Standby system  New control system
(4) System switching (Resetting of control system or hardware failure has occurred.)
Order of priority
High 1

2

3
Low
4

1 FUNCTIONS
1.8 Redundant Function
1
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