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TROUBLESHOOTING
CHAPTER8 TROUBLESHOOTING
This chapter provides troubleshooting methods of redundant system.
Error codes, special relays, and special registers of redundant CPU are not covered in this
manual. Refer to the following manual, for error codes, special relays, and special
registers of redundant CPU.
QCPU User's Manual (Hardware Design, Maintenance and Inspection)
The CPU module status can be confirmed by the LEDs, which are situated on the front
face of the CPU module. The CPU module LEDs necessary for troubleshooting of
redundant system are explained here.
Diagram 8.1 CPU Module LEDs
Table8.1 LED Names and Explanations
No.
Name
Explanation
1)
MODE LED
Indicates the CPU module mode.
On (Green)
: Q Mode.
Flashing (Green) : External I/O Forced ON/OFF has been registered.
2)
RUN LED
Indicates the CPU module operation status.
On
: The CPU is Running. The RUN/STOP switch: RUN position.
Off
: The CPU has Stopped. The RUN/STOP switch: STOP position.
The standby system CPU module in backup mode.
(The RUN/STOP switch: RUN position.)
An error that stops operation has been detected.
Flashing : The RUN/STOP switch is set to the STOP position to write parameters/
programs into CPU, and then the switch is returned from the STOP to
RUN position.The standby system CPU module for which the operation
mode is switched from backup mode to separate mode.
3)
ERR.LED
On
: The self diagnostics error that does not stop the operation (other than
battery error) is detected.
(The settings have been made by the parameter so that the operation is
continued when an error is detected.)
Off
: Normal.
Flashing : An error that stops operations has been detected.
Automatic write to the standard ROM is completed (BOOT LED is also
flashing.)
Q12PRHCPU
MODE
RUN
ERR.
USER
BAT.
BOOT
BACKUP
SYSTEM B
SYSTEM A
CONTROL
7)
2)
3)
4)
5)
6)
1)
8)
9)
10)