Mitsubishi Melsec-Q Series User Manual page 431

Error
Code Error Contents and Cause
(SD0)
[STANDBY]
The control system has been switched to the
standby system in a redundant system. (Detected
by the CPU that was switched from the control sys-
tem to the standby system)
Since this error code does not indicate the error
information of the CPU module but indicates its sta-
tus, the error code and error information are not
stored into SD0 to 26, but are stored into the error
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log every system switching.
(Check the error information by reading the error
log using GX Developer.)
■Collateral information
• Common Information:Reason(s) for system
switching
• Individual Information:–
■Diagnostic Timing
• Always
[CAN'T SWITCH]
System switching cannot be executed due to
standby system error/ tracking cable error/ online
module change in execution at separate mode.
Causes for switching system at control system are
as follows:
• System switching by SP. CONTSW instruction
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• System switching request from network module
■Collateral information
• Common Information:Reason(s) for system switching
• Individual Information:Reason(s) for system switching
failure
■Diagnostic Timing
• At switching execution
[STANDBY SYS. DOWN]
Any of the following errors was detected in the
backup mode.
• The standby system has not started up in the
redundant system.
• The standby system has developed a stop error
in the redundant system.
• The CPU module in the debug mode was con-
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nected to the operating control system.
(This can be detected from the control system of
the redundant system.)
■Collateral information
• Common Information:–
• Individual Information:–
■Diagnostic Timing
• Always
Corrective Action
–
• Check the status of the standby system and
resolve the error.
• Complete the online module change.
• Check whether the standby system is on or not,
and if it is not on, power it on.
• Check whether the standby system has been
reset or not, and if it has been reset, unreset it.
• Check whether the standby system has devel-
oped a stop error or not, and if it has developed
the error, remove the error factor and restart it.
• When the CPU module in the debug mode was
connected to the control system operating in the
backup mode, make connection so that the con-
trol system and standby system are combined
correctly.
CHAPTER12 TROUBLESHOOTING
LED Status Corresponding
CPU Status CPU
RUN:
On
ERR.:
Off
CPU Status:
No error
RUN:
On
ERR.: QnPRH
On
CPU Status:
No error
RUN:
On
ERR.:
On
CPU Status:
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