Omron NJ301-1100 User Manual

5 Troubleshooting
5-94
NJ-series CPU Unit Hardware User’s Manual (W500)
5-2-5 Troubleshooting Errors That Are Not in the CPU Unit
Input Units
No. Abnormal condition Cause Correction
1 None of the inputs turn
ON and the operation
indicators do not light.
1. The external input power is not sup-
plied.
Supply suitable input power.
2. The external input power supply volt-
age is low.
Maintain the external input power
supply voltage within the rating.
3. Loose screws on the terminal block Tighten the screws.
4. Faulty contact on the terminal block or
connectors
Replace the terminal block or
connector.
2 None of the inputs turn
ON, but the operation
indicators are lit.
Faulty circuits in the Input Unit Replace the Input Unit.
3 None of the inputs turn
OFF.
Faulty input circuits Replace the Input Unit.
4 A specific input does not
turn ON.
1. Faulty input device Replace the input device.
2. Input wiring is broken. Check the input wiring.
3. Loose screws on the terminal block Tighten the screws.
4. Faulty contact on the terminal block or
connectors
Replace the terminal block or
connector.
5. The external input ON time is too short
or the input response time is too long.
Adjust the input device or correct
the setting of the input response
time.
6. Faulty input circuits Replace the Input Unit.
7. An input bit is used in an Out instruc-
tion in the user program.
Correct the user program.
5 A specific input does not
turn OFF.
1. Faulty input circuits Replace the Input Unit.
2. An input bit is used in an Out instruc-
tion in the user program.
Correct the user program.
3. The leakage current or residual volt-
age is too large.
Replace the external load or add
a dummy resistor.
4. More than one power supply is used
and unwanted current paths exist.
Check the external circuits.
6 The input bits turns ON
and OFF irregularly.
1. The external input power supply volt-
age is low or unstable.
Maintain the external input power
supply voltage within the rating.
2. Malfunction caused by noise Implement noise countermea-
sures.
• Attach a surge suppressor.
• Install an isolation transformer.
• Use a shielded cable between
the Input Unit and the load.
• Check the setting of the input
response time.
3. Loose terminal block Tighten the screws.
4. Faulty contact on the terminal block or
connectors
Replace the terminal block or
connector.

Omron NJ301-1100 Specifications

General

Brand	Omron
Model	NJ301-1100
Category	Controller
Language	English