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

HMIs versus SCADA

It is very common for people, even experienced automation engineers, to confuse HMIs with SCADA systems. SCADA stands for Supervisory Control And Data Acquisition. When a person correctly refers to SCADA, they are referring to systems that include sensors, PLCs, RTUs, control software such as HMIs, and so on. SCADA systems are more for larger systems, for example, systems that will supervise whole plants.

In contrast, an HMI is designed to control a single machine. A machine’s HMI will usually be placed near the machine, and it exists to operate that machine or a very limited group of related machines. Depending on the system you used to develop the HMI, you can network HMIs to a SCADA system. To do this, you will need to have a SCADA system that can support this type of functionality.

As such, the best way to think of the differences between HMIs and SCADA systems are as follows:

  • HMIs: HMIs control a machine or small groups of machines. The HMI...