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MELSEC-Q
4 SETTING AND PROCEDURE BEFORE OPERATION
(b) Setting the mode when performing the forward loop/reverse loop test on the
redundant system
When conducting the forward loop/reverse loop test on the redundant
system, set the operation mode of the redundant CPU to the backup mode
in advance.
When it the power supplies of both the systems cannot be powered on/off,
perform the forward loop/reverse loop test in the separate mode.
The table below lists the mode settings when conducting the forward
loop/reverse loop test on the redundant system.
Target station Set-up
Test target station
Redundant
system
In the backup
mode
Set the mode to "Forward
loop test" or "Reverse
loop test".
In the separate
mode
Non-test target station
Redundant
system
In the backup
mode
Set the mode to "Offline".
In the separate
mode
Set the mode to "Online".
Remote I/O station Set the mode to "Online".
The figure below shows the settings when the forward loop test is executed
on the system A (station No. 1) of the redundant system (in the backup
mode).
Redundant
CPU
Station
No. 1
Redundant
CPU
Station
No. 0
Power
supply
module
QJ72
LP25
QJ72
LP25
Control system
(system A)
Standby system
(system B)
Set the mode of the system B (station No. 1)
to "offline."
Set the mode of the system A (station No. 0)
to "forward loop test."
Remote I/O station Remote I/O station
Station
No. 2
Station
No. 3
Power
supply
module
Power
supply
module
Power
supply
module