Troubleshooting; Cpu Unit's Err/Alm Indicator Lit Or Flashing; Remote I/O Communications Disabled - Omron CJ1W-DRM21 Operation Manual

9 Troubleshooting and Maintenance
9-3

Troubleshooting

9-3-1

CPU Unit's ERR/ALM Indicator Lit or Flashing

Error
An I/O setting check error occurred.
Special Unit access is denied.
An I/O Bus check error occurred.
Note Refer to the NJ-Series CPU Unit Hardware User's Manual (Cat. No. W500) and NJ-Series CPU
Unit Software User's Manual (Cat. No. W501) for more details on these errors.
9-3-2

Remote I/O Communications Disabled

Error
All of the DeviceNet Unit's indicators are OFF.
The DeviceNet Unit's MS indicator is ON and
green, but the NS indicator remains OFF.
(The green NS indicator normally goes ON
about 2 seconds after the green MS indicator
goes ON.)
9-32
• Make sure that the Unit is mounted properly.
• The CPU Bus Unit model registered in the Unit Configuration in the CPU
Unit does not match the actual Unit Configuration. Compare using "Syn-
chronize" operation and use one of the following procedures.
• Correct the Unit number setting
• Correct the project Unit Configuration and transfer to the CPU Unit
• Make sure that the Unit is mounted properly.
• Restart the Unit. If operation is not restored even after the Unit is
restarted, replace the Unit.
• Make sure that the Unit is mounted properly.
• Restart the Unit. If operation is not restored even after the Unit is
restarted, replace the Unit.
• Check whether power is being supplied to the NJ-series Controller.
• Check whether the DeviceNet Unit is mounted in the Backplane cor-
rectly.
• When a watchdog timer (WDT) error has occurred in the CPU Unit,
follow the procedures described in the CPU Unit's manual to correct
the problem.
• All of a CJ1W-DRM21 Unit's indicators will be OFF when a CPU Bus
Unit error has occurred.
• Restart the Unit. If operation is not restored even after the Unit is
restarted, replace the Unit.
• If the DeviceNet Unit's 7-segment indicator is displaying an error
code, refer to the tables in 9-1 Troubleshooting with the DeviceNet
Unit Indicators.
• Make sure that the master's unit number setting is correct.
• Make sure that the unit number is not duplicated on another Special
Unit.
• Use the Synchronize function to compare the Unit Configurations.
• Use one of the following procedures according to the comparison
results.
• Correct the Unit number setting
• Correct the project Unit Configuration and transfer to the CPU Unit
• Restart the Unit. If operation is not restored even after the Unit is
restarted, replace the Unit.
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
Probable cause
Probable cause