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5.1 Basic Concept of Redundant System
5.1.3 Operation Mode
5
REDUNDANT SYSTEM FUNCTIONS
(2) Separate Mode
The separate mode is for maintenance without stopping control.
In the separate mode, different programs can be run in the control system and
standby system CPU modules. While continuing the system control in the control
system, program of standby system can be corrected and operation of program can
be checked by using the data tracked from the control system.
(a) Enabling/Disabling the Tracking Function
In the separate mode, it is possible to select whether the tracking function is
enabled or not, in order to perform the tracking.
Refer to Section 5.5 for the tracking function.
(b) Confirming the Separate Mode
Confirm that the redundant system is running in the backup mode by checking the
"BACKUP" LEDs of CPU modules.
Refer to the following manual, for details on the CPU module LED:
QCPU User's Manual (Hardware Design, Maintenance and Inspection)
Table5.6 Checking the "BACKUP" LED to Confirm the Separate Mode
CPU Module LED
LED Status
LED Name
Control
System
Standby
System
BACKUP
ON
(amber)
ON
(amber)
Q12PRHCPU
MODE
RUN
ERR.
USER
BAT.
BOOT
BACKUP
CONTROL
SYSTEM A
SYSTEM B