PLC Learning

This offers ways in which you can learn PLC programming.

Building a PLC Program Part 3 – Traffic Light

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In part 1, we looked at writing PLC programs to control a traffic light using discrete bits and timed sequencing using indirect addressing. Part 2 used indirect addressing for inputs and output to control the program’s sequence of pneumatic (air) cylinders. We will now return to the traffic light application and expand our program significantly. … Read more

How PLC Outputs Work – Discrete and Analog

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This post is a further follow-up from my original ‘Here’s a Quick Way to Understand PLC Inputs and Outputs.’ There are two different kinds of PLC outputs, Discrete and analog. Discrete outputs are either ‘ON’ or ‘OFF’; 1 or 0. You can think of them as a single light bulb. Analog outputs have a range … Read more

How PLC Inputs Work – Discrete and Analog

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This post is a further follow-up from my original ‘Here’s a Quick Way to Understand PLC Inputs and Outputs.’ There are two different kinds of PLC inputs, Discrete and analog. Discrete inputs are either ‘ON’ or ‘OFF’; 1 or 0. You can think of them as a single switch. Analog inputs have a range to … Read more

Learn PLC Programming without spending a dime!

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plc basics programmable logic controller

I have been writing PLC programs for over 20 years. I often get asked what the best way to learn PLC programming is. Programming in the way I was taught in college was with the Motorola 6809. (Yes, I know that I am dating myself) This was microprocessor programming, but it was the best way … Read more

How to Troubleshoot a PLC – Ladder Logic

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We will look at how to troubleshoot a plc racing condition. Two examples are explained in racing conditions in the PLC. The PLC will update only at the end of the program logic. Items set will not happen until the I/O is refreshed. How to trigger events when you want them is discussed. Your control … Read more

Here is a Method for a Faster PLC Program

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PLC programming involves both direct and indirect addressing. Direct address programming involves writing each ladder logic rung to do the operation required. We often forget about using powerful indirect addressing to solve our logic. Indirect Addressing – Faster PLC Program The below-animated picture will show a simple example of using indirect addressing. This will use … Read more