Book Image

Mastering PLC Programming

By : Mason White
Book Image

Mastering PLC Programming

By: Mason White

Overview of this book

Object-oriented programming (OOP) is a new feature of PLC programming that has taken the automation world by storm. This book provides you with the necessary skills to succeed in the modern automation programming environment. The book is designed in a way to take you through advanced topics such as OOP design, SOLID programming, the software development lifecycle (SDLC), library design, HMI development, general software engineering practices, and more. To hone your programming skills, each chapter has a simulated real-world project that’ll enable you to apply the skills you’ve learned. In all, this book not only covers complex PLC programming topics, but it also removes the financial barrier that comes with most books as all examples utilize free software. This means that to follow along, you DO NOT need to purchase any PLC hardware or software. By the end of this PLC book, you will have what it takes to create long-lasting codebases for any modern automation project.
Table of Contents (25 chapters)
1
Part 1 – An Introduction to Advanced PLC Programming
6
Part 2 – Modularity and Objects
10
Part 3 – Software Engineering for PLCs
14
Part 4 – HMIs and Alarms
19
Part 5 – Final Project and Thoughts

Functions — Making Code Modular and Maintainable

As a college-level programming instructor, the first thing I like to teach after teaching the basics, such as loops and flow control, is functions. For many new and non-classically trained programmers, the purpose of functions often makes little sense. For the most part, new and inexperienced software developers see functions as a useless code organization technique that convolutes code. However, I usually counter this logic by stating that programmers should be like sewists. When a sewist creates a quilt, they take individual patches and sew them together to create the quilt. When it’s time to create the quilt, there is little concern about creating a patch. The only thing they are worried about is integrating the patch into the quilt as a whole.

For the most part, a programmer should consider themselves to be a sewist of software and the patch of choice should be functions. As we will explore in this chapter, the code...