Troubleshooting Unit Errors - Omron CP1L-EL20DR-D Operation Manual

Troubleshooting Unit Errors

12-4 Troubleshooting Unit Errors
CPU Unit
Symptom
POWER indicator is not lit.
RUN indicator is not lit.
RUN indicator on the CPU Unit is lit.
Bits do not operate past a certain point.
Error occurs in units of 8 or 16 points.
I/O bit turns ON.
All bits in one Unit do not turn ON.
Inputs
Symptom
Not all inputs turn ON or indi-
cators are not lit.
Not all inputs turn ON even
though the indicator is lit.
Not all inputs turn OFF.
Specific bit does not turn ON. (1) Input device is faulty.
Specific bit does not turn
OFF.
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
PCB short-circuited or damaged.
(1) Error in program (fatal error)
(2) Power line is faulty.
Internal circuitry in the Unit is faulty.
Cause
(1) External power is not supplied for the
input.
(2) Supply voltage is low.
(3) Terminal block mounting screws are
loose.
(4) Faulty contact of terminal block connec-
tor.
Input circuit is faulty. (There is a short at the
load or something else that caused an over-
current to flow.)
Input circuit is faulty.
(2) Input wiring disconnected.
(3) Terminal block screws are loose.
(4) Faulty terminal block connector contact. Replace terminal block connector.
(5) Too short ON time of external input.
(6) Faulty input circuit
(7) Input bit number is used for output
instruction.
(1) Input circuit is faulty.
(2) Input bit number is used for output
instruction.
(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
Replace Unit.
Correct program.
Replace Unit.
Remedy
Supply power
Adjust supply voltage to within rated range.
Tighten screws.
Replace terminal block connector.
Replace Unit.
Replace Unit.
Replace input devices.
Check input wiring
Tighten screws
Adjust input device
Replace Unit.
Correct program.
Replace Unit.
Correct program.
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 12-4
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