Free PLC Training: Learn PLC Programming Online

Note: Updated For 2026

Books can teach you a lot about PLC programming, from ladder logic and structured text to working with specific platforms such as the Siemens S7-1200.

The collection below brings together the best PLC programming books. Some are free PDF downloads; others are sold as printed books or e-books.

I selected these books to help you choose from the many PLC programming titles available and spend your time and money on resources you can learn from.

You will find many types of PLC programming books online. Most cover PLC programming in general, including how a PLC works and how to use its programming languages. One common [...]

This is the second part of my ladder logic tutorial. In part 1 of the ladder logic tutorial, I introduced the basics of ladder logic and some of the basic instructions. Here, we will build on that starting point.

In this second part, I will show you how to solve practical problems with ladder logic and use those solutions to build PLC programs. As we work through the examples, you will also learn several more ladder logic instructions:

A PLC counter counts up or down within a function block until it reaches a limit. Reaching that limit sets the output.

In PLC programming, counting tracks how often a process completes or how many products it produces. A PLC counter works as a digital tally counter to help manage these industrial tasks efficiently.

SCADA stands for “Supervisory Control and Data Acquisition”.

Engineers usually shorten that long name to “SCADA System”, or simply “SCADA”.

The basics of SCADA include its systems and architecture, applications and programming. These are the topics covered here.

PLC timers control when events happen, from starting a motor to setting a signal’s duration. They can seem tricky when you’re learning, but become straightforward with practice. Understanding how they work lets you choose and use them in your programs. The examples below connect each timer’s name to its behavior, so you can understand what happens when it runs.

In automation and manufacturing, you will inevitably encounter ISA-88, also called S88.

Published by The International Society of Automation (ISA), the standard defines models and terminology for batch control. Its aim is to standardize batch control so automation suppliers can more easily integrate, communicate and configure batches. Europe has adopted it as IEC 61512-1.

Most manufacturers and automation suppliers working with batch control use the standard today. Food and medicine producers in particular use all or part of it to keep track of batch production.

Machinery safety is an important but often undertaught subject, and the terminology in ISO 12100 can make risk assessment difficult to understand. This example works through the procedures and methods in ISO 12100 and the old ISO 14121-2.

Risk assessment identifies risks and hazards in a machine design. As machine designers, we must make our machines safe for people to operate. Finding and eliminating those risks is ultimately our responsibility.

Safety relays help you build the safety circuits used in machine design. To understand their purpose in keeping operations safe, you need to know the basics of how the relays work and why these circuits are used.

Safety can become confusing because it comes with a large amount of terminology. These terms originate in the standards that describe safety circuits and functional safety. Those standards also describe safety relays and their operation.

Are you looking for a course in PLC programming?

You can choose from many PLC training courses, including free options, but their reliability and quality differ. I put this guide together to help you find the course that suits your needs.

Compare what each course teaches and what it costs so you can decide which one suits you and whether it is worth paying for.

Our PLC training selections cover Allen Bradley (Rockwell Automation), Siemens, Omron and Factory Automation, so you can find a course for the platform you want to learn.

Compare the Best Online PLC Training Courses of 2026 below.

What is PLC Training?PLC training is training designed to help [...]

Do you know how to scale an analog input or wire an analog output?

Analog signals can be difficult to work with in PLC programming. Wiring an analog input or output and using it in your program can both be tricky. Most example PLC programs use digital signals, as do most examples in my Structured Text Tutorial.

Many of you have asked how to use analog signals in PLC programming, so I wrote this article to explain them. Analog signals are common in PLC programs and in a SCADA system. We will cover how to connect a 4-20mA analog transmitter to your PLC and how to use that signal once it reaches your PLC program. We will also examine how to scale an analog signal in [...]

The Function Block Diagram (FBD) is an official, widely used PLC programming language. It gives you a simple graphical way to connect functions in a PLC program. Function Block Diagram is easy to learn and supports many possibilities.

A PLC programming language I rate among the best visual languages is ladder logic, also called ladder diagram (LD).

Ladder logic is much more visual than most programming languages. That visual approach often makes the language easier for people to learn.

Ladder logic looks similar to electrical relay circuits. If you already have some experience with relay control and electrical circuits, that familiarity will likely help you learn it faster.

You don’t need that background to begin. When I first learned ladder logic, I didn’t understand relays either.

This Arduino tutorial starts from scratch and works through the basics, so you can follow along without previous experience. I’ll guide you through setting up your computer and writing your very first program for the Arduino Uno board. We will begin with the setup and build from there.

If you are new to PLC programming, this starter kit teaches you the fundamentals.

The Siemens LOGO Starter Kit suits beginners because it is small and inexpensive, with software that is easy to use.

You can build and simulate ladder logic PLC programs for free. Follow this guide to download and install RSLogix Micro Starter Lite and RSLogix Emulate 500, then use them to test your PLC programs at no cost.

Do you find large ladder diagrams hard to read, including your own?

Although ladder logic is easy for beginners to learn, reading and understanding it can be difficult. For that reason, some programmers prefer Structured Text for PLC programming. This tutorial explains how it works.

The Siemens S7-1200 PLC is known for being easy to use and suitable for beginners. Its Starter Kit includes SIMATIC S7 TIA Portal software to help you begin programming Siemens PLCs. You can also manage the S7-1200 PLC from your smartphone.

Once you understand normally open and normally closed contacts, you can decide where and how to use them in PLC programming. This means relating your PLC program to the physical PLC inputs.

Ladder logic symbols are the building blocks of ladder diagrams. This guide covers the symbols defined in IEC 61131-3 and includes downloads in several formats, including a PDF you can keep for reference.

Here is how I often begin a PLC programming project:

When I develop a PLC program, I steal other people’s ladder logic.

I use other people’s ladder logic examples to find ideas and solutions for my PLC programs.

When programming a PLC with ladder logic, you will sometimes encounter a problem you have solved before. Looking through ladder logic program examples can help you find a solution quickly. An example may even suggest a better approach than the one you first had in mind.

This is an introduction to PLC logic and how to use it to build PLC programs from simple electrical circuit diagrams. In this article, I will work with combinatorial logic to put together the functionality of a PLC program.

To bring the example closer to a real PLC programming language such as ladder logic, I will draw the PLC logic as contacts and relays in an electrical circuit.

The Siemens S7-200 is a low-cost option for starting PLC programming. Its straightforward design and limited functions make it approachable for beginners, while still giving you reasons to choose it. This guide takes you through getting started with the S7-200 and programming it.

Thermocouples measure temperature quickly across a wide range. There are several types to choose from, each with its own temperature range and tolerance. Choose the thermocouple type that suits your project.

This guide explains how to make an Ethernet cable, also called a network cable or patch cable. Making your own cables reduces what you spend on them. You can also cut each Ethernet cable to the exact length you need and choose the wiring that suits the connection you are making. You can follow these instructions for cables you use at home or at work.

Profibus or Process Field Bus is a field bus communications standard for the automation industry. Its industrial computer network is designed to withstand high levels of noise. With its two-wire cable, Profibus supports different network topologies such as a star or a tree, a line or a combination of these.

Understanding a PLC begins with its basic architecture and the hardware inside it. The components are the physical building blocks that make up the PLC. Knowing what each of these parts does, and how it fits into the system, makes it easier to understand the PLC as a whole.

Having looked at what hardware is inside the PLC, we can now look at the software inside the PLC and how it runs.

Every PLC has a scan time and a scan cycle. Understanding these terms explains how the PLC works and how the software inside it runs.

During a scan cycle, the PLC gathers the inputs and runs your PLC program before updating the outputs.

The PLC needs some time to complete this process. That time is often measured in milliseconds (ms).

We call the amount of time the PLC needs to complete one full scan cycle the PLC’s scan time.

Let’s start with a few basic concepts that explain how a PLC program works.

Once you understand the PLC scan time, you can examine how the PLC program works. Combinatorial logic explains how logic combines true and false, its two states. Combining logic is also the basis of PLC programming. Since the two share the same fundamentals, combinatorial logic gives you a useful starting point for learning to program a PLC.