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Chapter 14
Documenting Your PLC System
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Objectives
Explain what is contained in a system documentation package.
Describe why a system documentation package should be developed.
State when the documentation package is usually developed.
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Objectives (cont’d.)
List what documentation features the typical PLC software development package offers.
Explain the value of documentation during troubleshooting.
Describe the value of documentation if you have to expand the present system.
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Objectives (cont’d.)
Explain what a rung description is.Describe a rung symbol and the
advantage of using symbols.State the value of documentation
during system start-up.Explain the value of
documentation during an outside service person’s service call.
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PLC System Documentation
A documentation package is an orderly collection of information concerning the configuration and operation of your system.
It is typically put together as system is designed.
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PLC System Documentation Usage
Installation Debugging Start-Up Maintenance Modification System duplication
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Why Add Documentation to User Program?
Assist installers to install and start up system.
Help maintenance individuals troubleshoot and maintain system.
Provide information to operators who must understand how system works.
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Why Add Documentation to User Program? (cont’d.)
Assist in answering system upgrade questions.
Enable outside service people understand system for maintenance, servicing or upgrade.
Allow easy reproduction of system.
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What Should Be Included in Documentation Package?
System overviewDiagram of system configurationI/O address assignmentsInternal coil address assignmentsData table assignments
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What Should Be Included in Documentation Package?
(cont’d.)
Program printoutControl program backupWiring diagrams
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Sample Diagram of System Configuration
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Typical Wiring for a 120 VAC Input Module
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Typical Wiring for a 120 VAC Output Module
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Diagram of System Configuration
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Seven-Slot Chassis with I/O Modules Assigned
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Internal Bit Allocation Table
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Timer Address Allocation Table
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Integer File Allocation Table
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Documentation and Software Packages
PLC program development software provides readily available documentation features:Hard copy print out of all data and
ladder filesCross-reference reportsHard copy of ladder rungsMemory usageProcessor configuration data
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Software Ladder Rung Documentation
Software packages provide ladder rung documentation as program is developed.
Rung documentation can be added later or modified by maintenance individuals.
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Software Ladder Rung Documentation
(cont’d.)
Software packages ladder rung documentation:Page titlesRung commentsInstruction symbolsInstruction descriptionsInstruction comments
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RSLogix 500 Ladder Documentation