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9 Troubleshooting and Maintenance
9-2
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
9-1
Indicator Error Displays
Indicators
Possible cause
Remedy
RUN
ERC
ERH
RDY
Lit
Not lit
Not lit
Lit
The Serial Communications Unit started normally.
---
Not lit
Lit
---
---
The Serial Communications Unit is found to be faulty
(by the hardware self-diagnostic function).
If the ERC indicator lights when the Serial
Communications Unit is mounted to another
CPU Unit, replace the Unit.
Not lit
Not lit
Lit
---
There is more than one identical unit number within
the same CPU Unit.
An initial recognition error occurred (the Serial Com-
munications Unit was not correctly recognized by the
CPU Unit).
Assign a unique unit number to each CPU Unit
on the CPU Rack and Expansion Racks.
After correcting the unit number setting, cycle
the power to the Controller.
If the ERH indicator lights up when the Serial
Communications Unit is mounted to another
CPU Unit, replace the Unit.
Not lit
Lit
Lit
---
An initial recognition error occurred (the Serial Com-
munications Unit was not correctly recognized by the
CPU Unit).
If the ERC and ERH indicators light when the
Serial Communications Unit is mounted to
another CPU Unit, replace the Unit.
Not lit
Not lit
Not lit
Not lit
The Power Supply Unit power supply reception is not
normal.
The Serial Communications Unit is not correctly
secured to the next Unit.
The Serial Communications Unit is not mounted in
an appropriate slot.
The Serial Communications Unit is faulty.
Check the power supply voltage and supply
the correct electric power to the Unit.
Firmly secure the Unit.
Mount the Unit in an appropriate slot.
If all the indicators are not lit when the Serial
Communications Unit is mounted to another
CPU Unit, replace the Unit.
Lit
---
Flash-
ing
---
A system setup error occurred.
Correct the System Settings, reset or restart
the Controller, or restart the port.
Lit
Lit
---
---
The error log EEPROM is faulty.
If the problem persists even if the power supply
is cycled, replace the Unit.
Lit
---
Lit
---
An error (such as a CPU Unit WDT error) occurred in
the CPU Unit.
A CPU Unit service monitoring error occurred.
A bus error occurred.
Eliminate the cause of the error. If the error
persists, replace the CPU Unit.
Check the operating environment and elimi-
nate the cause of the error. (Check to be sure
that the problem is not caused by another CPU
Bus Unit with the same unit number.)
Check the operating environment and elimi-
nate the cause of the error.
Firmly secure the Unit.