Omron NJ501-1400 User Manual page 276

5 Troubleshooting
No. Abnormal condition
6 A specific output does
not turn OFF and the
operation indicator is lit.
7 The output turns ON
and OFF irregularly.
8 Abnormal operation
occurs for the output
points for the same
common (8 or 16
points).
9 The output operation
indicators do not light
even though operation
is normal.
10 The ERR indicator (load
short-circuit alarm) is lit
and the output is OFF.
5-96
Cause
1. The output bit is used in more than one
Out instruction in the user program.
2. Faulty output circuits
1. The load power supply voltage is low
or unstable.
2. The output bit is used in more than one
Out instruction in the user program.
3. Malfunction caused by noise
4. Loose terminal block
5. Faulty contact on the terminal block or
connectors
1. Loose screws on the common terminal Tighten the screws.
2. Faulty contact on the terminal block or
connectors
3. The fuse in the Output Unit has burned
out due to overcurrent, e.g., from a load
short-circuit.
4. Faulty circuits in the Output Unit
5. Faulty CPU Unit
6. Load short-circuit protection has oper-
ated. (You can confirm this on an indica-
tor.)
Faulty LEDs or LED circuits
The load is short-circuited externally or
disconnected.
NJ-series CPU Unit Hardware User's Manual (W500)
Correction
Correct the user program so that
only one Out instruction controls
the output bit.
Replace the Output Unit.
Maintain the load power supply
voltage within the rating.
Correct the user program so that
only one Out instruction controls
the output bit.
Implement noise countermea-
sures.
• Attach a surge suppressor.
• Install an isolation transformer.
• Use a shielded cable between
the Output Unit and the load.
Tighten the screws.
Replace the terminal block or
connector.
Replace the terminal block or
connector.
Replace the Output Unit.
Replace the Output Unit.
Replace the CPU Unit.
Check the load.
Check the output wiring.
Replace the Unit.
Refer to A-4-1 Load Short-circuit
Protection and Line Disconnec-
tion Detection for CJ1W-OD202.