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

Exploring common HMI controls

All systems need some way for the operator to send input signals and receive feedback. For purely physical systems, these input devices are things such as switches, buttons, and so on for the inputs while things such as LEDs and gauges are used for the outputs. However, this can be costly and, in the modern computer-driven world, unnecessary as we can simply program in our controls. As such, the remainder of this section will explore software-based controls.

Flip switches

As we all learned in high school, a switch causes a break in a circuit that will essentially cause the flow of electricity to stop when it reaches the switch. In other words, with the switch closed, the electricity is free to flow in the circuit, which will cause the equivalent of a TRUE condition. If the switch is open, the electricity will not be allowed to flow throughout the circuit, which will cause a FALSE condition. In terms of HMIs, a switch can be thought of in a similar...