Chapter 4 Troubleshooting
4-1
Chapter 4 Troubleshooting
The chapter describes types of potential errors that occur while operating the system, causes of errors, how to detect them and corrective
measures.
4.1 Basic Troubleshooting Procedure
To improve the reliability of a system, it is important to take a corrective measure promptly if a trouble occurs as well as to use highly reliable
devices. To operate a system immediately, it is the most important to quickly detect potential causes of a trouble and take corrective measures.
To troubleshoot the system correctly, make sure to take the following cautions and procedures.
1) Check by visual inspection
Please check the followings visually.
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Operation status(Stop, Run)
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Power On/Off status
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I/O device status
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Wiring status(I/O wiring, extension and communication cable)
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Check the status of each display(POWER LED, RUN/STOP LED, I/O LED and etc), connect to peripherals and check the operation
condition and program
2) Check any abnormality
Please observe how a fault changes by executing the followings.
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Move the key switch to STOP and turn it On/Off
3) Restricting Range
Estimate by which factor a fault occurs by the following methods.
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Is it from the PLC or external factor?
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I/O module or others?
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PLC program?