Troubleshooting Unit Errors - Omron CP1H-X40D Operation Manual

Troubleshooting Unit Errors

11-4 Troubleshooting Unit Errors
CPU Unit
Symptom
POWER indicator is not lit.
RUN indicator is not lit.
RUN indicator on the CPU Unit is lit.
Special I/O Unit or CPU Bus Unit does
not operate or malfunctions.
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.
Special I/O Units
Symptom
The ERH and RUN I/O refreshing is not being performed for the
indicators on the Spe- Unit from the CPU Unit (CPU Unit monitoring
cial I/O Unit are lit. error).
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.
618
Cause
PCB short-circuited or damaged.
(1) Error in program (fatal error)
(2) Power line is faulty.
Internal circuitry in the Unit is faulty.
(1) The I/O Connecting Cable is faulty.
(2) The I/O bus is faulty.
Refer to the operation manual for the Special I/O Unit to troubleshoot any
other errors.
Cause
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.
Remedy
Replace Unit.
Correct program.
Replace Unit.
Replace Unit.
Replace Unit.
Replace Unit.
Remedy
Enable cyclic refreshing for the Unit in the PLC
Setup, or make sure that the Unit is refreshed
from the program using IORF at least once
every 11 s.
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.
Section 11-4