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PLC Programming Lesson 2: PLCLogix Tools And Features

Use built-in PLCLogix tools to program, navigate, monitor, and troubleshoot more efficiently

Lesson objective: Examine five PLCLogix 500 features intended to make programming and troubleshooting easier: Instruction Help, multiple windows, the Project Tree, Processor Status, and the Custom Data Monitor.

There are many valid ways to create PLC programs, and you will develop a style that works for you. Regardless of programming style, good documentation remains important so another person can follow the program logic.

Before you begin: Access to the PLCLogix 500 or PLCLogix 5000 training simulator is required to complete the hands-on lesson series. Complete the Getting Started guide and Lesson 1 first if you are new to PLCLogix. The screenshots in this lesson use PLCLogix 500.

Instruction Help

PLCLogix includes built-in instruction help under the Help menu. In the example below, the TON timer instruction is identified as item 1. Select Help > Instruction Help, identified as item 2, to open the internal instruction reference.

The RSLogix 500 Instruction Set Help window opens with a table of available instructions. Locate TON in the instruction table.

RSLogix 500 Instruction Set Help window listing PLC instructions with TON identified — The internal Instruction Help window lists available instructions by acronym.

Click the TON entry to display help for the Timer On Delay instruction. A detailed description and the available parameters are shown.

SLC Instruction Set Help showing detailed help and parameters for the TON Timer On Delay instruction — Selecting TON displays the instruction description, parameters, and usage information.

PLCLogix also provides a separate choice under the Help menu called SLC 500 Instruction Set. Selecting it opens the Rockwell SLC 500 series Instruction Set guide as a PDF in a separate window. You can download and save that PDF for future reference.

Rockwell SLC 500 Instruction Set PDF open in Adobe with an inset showing the PLCLogix Help menu SLC 500 Instruction Set choice — The SLC 500 Instruction Set menu choice opens Rockwell's reference PDF in a separate window.

Multiple Windows

PLCLogix includes several 3D environments that can be used with the ladder programs you create, such as the Wind Turbine application shown below. The simulator window can remain visible alongside the ladder program while the simulation runs, helping you confirm program behavior.

PLCLogix 500 ladder program displayed with the Wind Turbine 3D simulator window — PLCLogix can display a 3D I/O World alongside the ladder program while the simulation runs.

Project Tree

The Project Tree gives access to subroutine files, I/O files, Processor Status, Force Files, the Custom Data Monitor, and other project resources. Use the Project Tree, identified as item 1, to navigate those resources.

Processor Status

One important project resource is the Processor Status file. It contains status-type bits and other information related to the processor and project. Select Processor Status from the Project Tree to open the status window.

The status file can be viewed in several formats. The normal status window is shown below.

PLCLogix 500 Processor Status window open over the ladder program — Processor Status provides access to processor and project status information.

Use the Radix drop-down, identified as item 1, and select Binary to display the processor status file as a binary table.

PLCLogix 500 Processor Status window with the Radix drop-down open and Binary selected — Select Binary from the Radix drop-down to view the status file as individual bits.

In Binary format, the state of each status bit is easy to see directly in the table.

PLCLogix 500 Status Table displayed in Binary radix with individual status bits visible — Binary view exposes the individual status bits in the status file.

Custom Data Monitor

Click the + sign next to Custom Data Monitor in the Project Tree, identified as item 1. This reveals the COM 0 Trends item, identified as item 2. Click the Trends item to open the data monitor.

When the Trends item is selected, the data plotting window opens. To monitor an instruction or instruction field, enter the parameter name or element address in the Tag Name list. During simulation, the value can be plotted or shown numerically in the graph and table depending on its data type.

After entering the variable to monitor, go online and start the reciprocal timer program with Start_PB. In the Trends window, enter O:2/0 as shown, then press Acquire Data, identified as item 1.

PLCLogix Trends window with O colon 2 slash 0 entered as a Tag Name and Acquire Data identified — Enter a tag or address and use Acquire Data while the simulation is running.

With the simulation running, the Trends window plots the value at O:2/0 in real time. The window also reports minimum and maximum values and can be resized so you can watch the ladder program while monitoring the plotted data.

PLCLogix Trends window plotting O colon 2 slash 0 as a repeating square-wave signal — The Trends window plots the monitored value in real time while the PLC simulation runs.

Self-check: Open each of the five tools covered in this lesson and confirm you can locate instruction help, display a simulator window with the ladder program, navigate the Project Tree, change Processor Status to Binary radix, and monitor a live value in the Custom Data Monitor.

Assigned by an instructor or supervisor? If you were asked to complete this lesson, save your PLC program and any work requested by your instructor or supervisor and share it with them when finished.

Need access to the required simulator? PLCLogix 500 Simulator | PLCLogix 5000 Simulator

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