Omron CJ2 CPU UNIT User Manual page 226

6 Troubleshooting
No.
7 Output irregularly turns ON/OFF.
8 Error occurs in units of 8 points
or 16 points, i.e., for the same
common.
9 Output indicator is not lit (opera-
tion is normal).
10 ERR indicator (load short-circuit
alarm) lights and outputs turn
OFF.
Special I/O Units
Refer to the Operation Manual for the Special I/O Unit to troubleshoot any other errors.
No.
1 The ERH and RUN indicators on
the Special I/O Unit are lit.
6-30
Symptom
Low or unstable load voltage.
Bit status controlled by multiple
instructions.
Malfunction due to noise.
Terminal block screws are loose.
Faulty terminal block connector
contact.
Loose common terminal screw.
Faulty terminal block connector
contact.
An overcurrent (possibly caused
by a short at the load) resulted in
a blown fuse in the Output Unit.
Faulty data bus.
Faulty CPU.
Faulty indicator.
An external short-circuit or dis-
connection occurred.
Symptom
Special I/O refreshing is not
being performed for the Unit from
the CPU Unit (CPU Unit monitor-
ing error).
Cause
Adjust load voltage to within
rated range.
Correct program so that each
output bit is controlled by only
one instruction.
Protective measures against
noise:
• Install surge suppressor.
• Install insulation transformer.
• Use shielded cables between
the Output Unit and the loads.
Tighten screws.
Replace terminal block connec-
tor.
Tighten screws.
Replace terminal block connec-
tor.
Replace fuse.
Replace Unit.
Replace CPU.
Replace Unit.
Refer to A-6-1 Load Short-circuit
Protection and Line Disconnec-
tion Detection for CJ1W-OD202.
Cause
Change the bit corresponding to
the unit number to 0 to enable
cyclic refreshing, or make sure
that the Unit is refreshed from
the program using IORF or
FIORF at least once every 11 s.
CJ2 CPU Unit Hardware User's Manual
Remedy
Remedy