649
Troubleshooting Unit Errors
Section 12-4
12-4 Troubleshooting Unit Errors
CPU Unit
Inputs
Symptom
Cause
Remedy
POWER indicator is not lit.
PCB short-circuited or damaged.
Replace Unit.
RUN indicator is not lit.
(1) Error in program (fatal error)
Correct program.
(2) Power line is faulty.
Replace Unit.
RUN indicator on the CPU Unit is lit.
Internal circuitry in the Unit is faulty.
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.
Symptom
Cause
Remedy
Not all inputs turn ON or indi-
cators are not lit.
(1) External power is not supplied for the
input.
Supply power
(2) Supply voltage is low.
Adjust supply voltage to within rated range.
(3) Terminal block mounting screws are
loose.
Tighten screws.
(4) Faulty contact of terminal block connec-
tor.
Replace terminal block connector.
Not all inputs turn ON even
though the indicator is lit.
Input circuit is faulty. (There is a short at the
load or something else that caused an over-
current to flow.)
Replace Unit.
Not all inputs turn OFF.
Input circuit is faulty.
Replace Unit.
Specific bit does not turn ON. (1) Input device is faulty.
Replace input devices.
(2) Input wiring disconnected.
Check input wiring
(3) Terminal block screws are loose.
Tighten screws
(4) Faulty terminal block connector contact.
Replace terminal block connector.
(5) Too short ON time of external input.
Adjust input device
(6) Faulty input circuit
Replace Unit.
(7) Input bit number is used for output
instruction.
Correct program.
Specific bit does not turn
OFF.
(1) Input circuit is faulty.
Replace Unit.
(2) Input bit number is used for output
instruction.
Correct program.
Input irregularly turns ON/
OFF.
(1) External input voltage is low or unstable. Adjust external input voltage to within rated
range.
(2) Malfunction due to noise.
Take protective measures against noise,
such as:
• Install surge suppressor.
• Install insulation transformer.
Install shielded cables between the Input
Unit and the loads.
(3) Terminal block screws are loose.
Tighten screws
(4) Faulty terminal block connector contact.
Replace terminal block connector.
Error occurs in units of
8 points or 16 points, i.e., for
the same common.
(1) Common terminal screws are loose.
Tighten screws
(2) Faulty terminal block connector contact.
Replace terminal block connector.
(3) Faulty data bus
Replace Unit.
(4) Faulty CPU
Replace CPU Unit.
Input indicator is not lit in nor-
mal operation.
Faulty indicator or indicator circuit.
Replace Unit.
Содержание CP1L-EL20DR-D
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Страница 22: ...xxii...
Страница 34: ...xxxiv Software Licenses and Copyrights 7...
Страница 178: ...144 Connecting the CX Programmer Section 5 1 Click the Connect button to connect and then connection online is completed...
Страница 192: ...158 Trial Operation and Debugging Section 5 3...
Страница 250: ...216 Automatic Clock Adjustment and Specifying Servers by Host Name Section 6 7...
Страница 666: ...632 Trouble Shooting Section 11 7...
Страница 696: ...662 Standard Models Appendix A...
Страница 805: ...771 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Страница 806: ...772 Connections to Serial Communications Option Boards Appendix F...
Страница 836: ...802 PLC Setup Appendix G...
Страница 838: ...804 TCP Status Transitions Appendix H...
Страница 840: ...806 Ethernet Network Parameters Appendix I...
Страница 842: ...808 Buffer Configuration CP1L EL EM Appendix J...
Страница 844: ...810 Ethernet Specifications Appendix K...
Страница 851: ...Index 817 work words 118 write protection 447...
Страница 852: ...818 Index...
Страница 854: ...820 Revision History...
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