22.
22 -
47
TROUBLESHOOTING
22.5 Fault Examples with I/O Modules
Examples of faults concerning I/O circuits and the corrective actions are explained.
22.5.1 Faults with the input circuit and the corrective actions
Examples of faults concerning input circuit and the corrective actions are explained.
Faults with the input circuit and the corrective actions
Situation
Cause
Countermeasure
E
xamp
le 1
Input signal does not
turn OFF.
• Leak current from input switch
(driven by a contactless switch, etc.)
• Connect an appropriate resistance so that voltage
between the terminals of the input module is
lower than the OFF voltage.
For CR constant,
0.1 to 0.47 F + 47 to 120 (1/2W) is
recommended.
Ex
ample 2
Input signal does not
turn OFF.
• Driven by a limit switch with a neon lamp
• Same as the example 1.
• Or, provide a totally independent display circuit
separately.
E
xam
ple 3
Input signal does not
turn OFF.
• Line capacity C of the leak current
twisted pair cable due to line capacity
of the wiring cable is about 100PF/m.
• Same as the example 1.
• However, leakage current does not occur when a
power supply is on the side of input device as
shown below.
Exam
ple 4
Input signal does not
turn OFF.
• Driven by a switch with LED indication
• Connect an appropriate resistance so that voltage
between the terminal of the input module and the
common is lower than the OFF voltage as shown
below.
* An example of calculation of resistor to be
connected is provided on the following page.
Summary of Contents for Q2ACPU
Page 1: ......
Page 2: ......
Page 221: ...12 12 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU ...
Page 222: ...12 13 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU ...
Page 237: ...12 28 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU MEMO ...
Page 271: ...16 13 16 POWER SUPPLY MODULE 4 Names and description of parts of the A66P ...
Page 343: ...21 21 13 MAINTENANCE AND INSPECTION 21 4 2 Replacement of the fuse for an output module ...
Page 357: ...22 12 22 TROUBLESHOOTING ...
Page 359: ...22 14 22 TROUBLESHOOTING MEMO ...
Page 429: ...App 32 APPENDICES Trigonometric function Classification Symbol Description ...
Page 537: ...App 140 APPENDICES REMARK 1 Message 1 An error code is displayed in 2 Alert 1 3 Alert 2 ...
Page 539: ...App 142 APPENDICES 2 Q2ACPU Q2ACPU S1 modules Unit mm inch ...
Page 541: ...App 144 APPENDICES 2 A66P power supply module Unit mm inch ...
Page 543: ...App 146 APPENDICES 3 A35B base unit 4 A38B A38HB A38HBEU base unit Unit mm inch Unit mm inch ...
Page 567: ...MEMO ...
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