Omron CJ - 09-2009 Operation Manual page 575

Troubleshooting Racks and Units
Output Units
Symptom
Not all outputs turn ON
Not all outputs turn OFF
Output of a specific bit num-
ber does not turn ON or indi-
cator is not lit
Output of a specific bit num-
ber does not turn ON (indica-
tor lit).
Output of a specific bit num-
ber does not turn OFF (indi-
cator is not lit).
Output of a specific bit num-
ber does not turn OFF (indi-
cator lit).
Output irregularly turns ON/
OFF.
Error occurs in units of
8 points or 16 points, i.e., for
the same common.
Output indicator is not lit
(operation is normal).
Cause
(1) Load is not supplied with power.
(2) Load voltage is low.
(3) Terminal block screws are loose.
(4) Faulty terminal block connector contact. Replace terminal block connector.
(5) An overcurrent (possibly caused by a
short at the load) resulted in a blown
fuse in the Output Unit. (Some Output
Units provide an indicator for blown
fuses.)
(6) Faulty I/O bus connector contact.
(7) Output circuit is faulty.
(8) If the INH indicator is lit, the Output OFF
Bit (A50015) is ON.
Output circuit is faulty.
(1) Output ON time too short because of a
mistake in programming.
(2) Bit status controlled by multiple instruc-
tions.
(3) Faulty output circuit.
(1) Faulty output device.
(2) Break in output wiring.
(3) Loose terminal block screws.
(4) Faulty terminal block connector faulty.
(5) Faulty output bit.
(6) Faulty output circuit.
(1) Faulty output bit.
(2) Bit does not turn OFF due to leakage
current or residual voltage.
(1) Bit status controlled by multiple instruc-
tions.
(2) Faulty output circuit.
(1) Low or unstable load voltage.
(2) Bit status controlled by multiple instruc-
tions.
(3) Malfunction due to noise.
(4) Terminal block screws are loose.
(5) Faulty terminal block connector contact. Replace terminal block connector.
(1) Loose common terminal screw.
(2) Faulty terminal block connector contact. Replace terminal block connector.
(3) An overcurrent (possibly caused by a
short at the load) resulted in a blown
fuse in the Output Unit.
(4) Faulty data bus.
(5) Faulty CPU.
Faulty indicator.
Remedy
Supply power
Adjust voltage to within rated range.
Tighten screws
Replace fuse or Unit.
Replace Unit.
Replace Unit.
Turn A50015 OFF.
Replace Unit.
Correct program to increase the time that
the output is ON.
Correct program so that each output bit is
controlled by only one instruction.
Replace Unit.
Replace output device.
Check output wiring.
Tighten screws.
Replace terminal block connector.
Replace relay or Unit.
Replace Unit.
Replace relay or Unit.
Replace external load or add dummy resis-
tor.
Correct program.
Replace Unit.
Adjust load voltage to within rated range
Correct program so that each output bit is
controlled by only one instruction.
Protective measures against noise:
(1) Install surge suppressor.
(2) Install insulation transformer.
(3) Use shielded cables between the Output
Unit and the loads.
Tighten screws.
Tighten screws.
Replace fuse or Unit.
Replace Unit.
Replace CPU.
Replace Unit.
Section 11-3
527