Omron CP1H CPU Operation Manual page 627

Troubleshooting Unit Errors
Symptom
Input irregularly turns ON/
OFF.
Error occurs in units of
8 points or 16 points, i.e., for
the same common.
Input indicator is not lit in nor-
mal operation.
Cause
(1) External input voltage is low or unstable. Adjust external input voltage to within rated
(2) Malfunction due to noise.
(3) Terminal block screws are loose.
(4) Faulty terminal block connector contact. Replace terminal block connector.
(1) Common terminal screws are loose.
(2) Faulty terminal block connector contact. Replace terminal block connector.
(3) Faulty data bus
(4) Faulty CPU
Faulty indicator or indicator circuit.
Remedy
range.
Take protective measures against noise,
such as:
• Install surge suppressor.
• Install insulation transformer.
Install shielded cables between the Input
Unit and the loads.
Tighten screws
Tighten screws
Replace Unit.
Replace CPU Unit.
Replace Unit.
Section 11-4
593