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

Chapter 2: Advanced Structured Text — Programming a PLC in Easy-to-Read English

  1. A pointer points to a memory address where a reference is similar to a pointer with less syntax and references another variable.
  2. The ^ symbol dereferences a pointer.
  3. TRY, CATCH, FINALLY
  4. Self-documenting code is logically named program attributes such as variable names.
  5. A good comment is a comment that is short and adds context to the code without cluttering it. A bad comment will not add any context to the code, is long, or will unnecessarily clutter the code.
  6. You should code to a variable so you only need to change values in one place, which will reduce the number of bugs in a program. Coding to a variable will also add context to what the value represents.