19.
19 -
1
LOADING AND INSTALLATION
19
LOADING AND INSTALLATION
This chapter describes the loading and installation procedures and precautions to obtain
the maximum system reliability and performance.
19.1 Fail-Safe Circuit Concept
When the PLC is powered ON or OFF, improper outputs may be generated temporarily
depending on the delay time and start-up time differences between the PLC power supply
and the external power supply for the control target (especially, DC).
For example, if the external power supply for a DC output module is powered ON and then
the PLC is powered ON, the DC output module may generate incorrect outputs temporarily
upon the PLC power-ON. To prevent this, it is required to build a circuit by which the PLC
is powered on first.
Also, an external power failure or PLC failure may lead to erroneous operation.
In order to eliminate the possibility of an system error and to ensure fail-safe operation,
create a circuit (emergency stop circuit, protection circuit, interlock circuit, etc.) outside the
PLC for the parts whose faulty operation could cause mechanical damage and/or
accidents.
A system design circuit example based on the above is provided later.
Содержание Q2ACPU
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Страница 221: ...12 12 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU ...
Страница 222: ...12 13 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU ...
Страница 237: ...12 28 12 OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU MEMO ...
Страница 269: ...16 11 16 POWER SUPPLY MODULE 2 Names and description of parts of the A62P A62PEU and A65P module ...
Страница 271: ...16 13 16 POWER SUPPLY MODULE 4 Names and description of parts of the A66P ...
Страница 343: ...21 21 13 MAINTENANCE AND INSPECTION 21 4 2 Replacement of the fuse for an output module ...
Страница 357: ...22 12 22 TROUBLESHOOTING ...
Страница 359: ...22 14 22 TROUBLESHOOTING MEMO ...
Страница 417: ...App 20 APPENDICES 3 Shift instructions Classification Symbol Description n bit shift 1 bit shift 1 word shift ...
Страница 429: ...App 32 APPENDICES Trigonometric function Classification Symbol Description ...
Страница 432: ...App 35 APPENDICES 15 Clock instructions Classification Symbol Description Clock data read write ...
Страница 537: ...App 140 APPENDICES REMARK 1 Message 1 An error code is displayed in 2 Alert 1 3 Alert 2 ...
Страница 538: ...App 141 APPENDICES APPENDIX 6 EXTERNAL DIMENSIONS Appendix 6 1 CPU Module 1 Q3ACPU Q4ACPU modules Unit mm inch ...
Страница 539: ...App 142 APPENDICES 2 Q2ACPU Q2ACPU S1 modules Unit mm inch ...
Страница 541: ...App 144 APPENDICES 2 A66P power supply module Unit mm inch ...
Страница 542: ...App 145 APPENDICES Appendix 6 3 Main Base Unit 1 A32B base unit 2 A32B S1 base unit Unit mm inch Unit mm inch ...
Страница 543: ...App 146 APPENDICES 3 A35B base unit 4 A38B A38HB A38HBEU base unit Unit mm inch Unit mm inch ...
Страница 567: ...MEMO ...
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