One of the best visual programming languages is a PLC programming language. It’s called ladder logic or ladder diagram (LD) and you can learn it very fast.
The smart thing about ladder logic is that it looks very similar to electrical relay circuits. So if you already know a little bit about relay control and electrical circuits, you can learn ladder logic even faster.
You can build ladder logic PLC programs and simulate them for free. This guide will show you how to download and install the popular RSLogix Micro Starter Lite and how to use the RSLogix Emulate 500 to simulate your ladder logic PLC programs.
Ladder logic symbols are the basic building blocks for ladder diagrams. Right here you will find all the ladder diagram symbols which are described in IEC 61131-3. The symbols are available for download in all formats and in a PDF-file.
This is an introduction to PLC logic. You can use PLC logic to build PLC programs with simple electrical circuit diagrams. In this article, I will use combinatorial logic to build the functionality of a PLC program.
And to get as close as possible to real a PLC programming language like ladder logic, the PLC logic in this article will be contacts and relays in an electrical circuit.
The basic architecture of a PLC is important to understand. It is crucial to know about the basic PLC hardware components that are inside PLC, because it will make your understanding of the PLC much easier. The hardware components are the physical building blocks of the PLC.
Now, that we know what hardware is inside the PLC, the next step will be to take a look at the software inside the PLC and how it runs. Every PLC has a scan time and a scan cycle. This is how the PLC and the software inside the PLC works. The scan cycle is the cycle of which the PLC gathers the inputs, runs your PLC program and then updates the outputs. This will take some amount of time often measured in milliseconds or ms. The amount of time it takes for the PLC to make one scan cycle is called the scan time of the PLC.
Before getting started with the PLC programming, let me illustrate some basic concepts about a PLC program.
If you know about the PLC scan time, you can start to explore how the PLC program works. Combinatorial logic gives you the basic understanding of how combining the two states – true and false with logic. The basics of PLC programming is combining logic. That’s why combinatorial logic can be a great way into PLC programming. Since the fundamentals of combinatorial logic and PLC programming are the same.