Documenting Your PLC System Chapter 15 Documenting Your PLC System

Objectives (1 of 2) 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. List what documentation features the typical PLC software development package offers. Explain the value of documentation during troubleshooting.

Objectives (2 of 2) Describe the value of documentation if you have to expand the present system. Explain a rung description. 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.

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 the system is designed.

PLC System Documentation Usage Installation Debugging Start-up Maintenance Modification System duplication

Why Add Documentation to User Program? Assists installers to install and start up system Helps maintenance individuals troubleshoot and maintain system Provides information to operators who must understand how system works Assists in answering system upgrade questions Enables outside service people understand system for maintenance, servicing, or upgrade Allows easy reproduction of system

What Should Be Included in Documentation Package? System overview Diagram of system configuration I/O address assignments Internal coil address assignments Data table assignments Program printout Control program backup Wiring diagrams

Sample Diagram of System Configuration

Typical Wiring for a 120 VAC Input Module

Typical Wiring for a 120 VAC Output Module

Diagram of System Configuration

Seven-Slot Chassis with I/O Modules Assigned

Internal Bit Allocation Table

Timer Address Allocation Table

Integer File Allocation Table

Documentation and Software Packages PLC program development software provides readily available documentation features. Hard copy print out of all data and ladder files Cross-reference reports Hard copy of ladder rungs Memory usage Processor configuration data

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. Software packages ladder rung documentation Page titles Rung comments Instruction symbols Instruction descriptions Instruction comments

RSLogix 500 Ladder Documentation