You're reading from Mastering PLC Programming The software engineering survival guide to automation programming

Product type Paperback

Published in Mar 2023

Publisher Packt

ISBN-13 9781804612880

Length 386 pages

Edition 1st Edition

Languages

PLC programming

Tools

PLC

Concepts

PLC Programming

Author (1):

M. T. White

View More author details

Table of Contents (25) Chapters

Preface

1. Part 1 – An Introduction to Advanced PLC Programming

2. Chapter 1: Software Engineering for PLCs FREE CHAPTER

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

4. Chapter 3: Debugging — Making Your Code Work

5. Chapter 4: Complex Variable Declaration — Using Variables to Their Fullest

6. Part 2 – Modularity and Objects

7. Chapter 5: Functions — Making Code Modular and Maintainable

8. Chapter 6: Object-Oriented Programming — Reducing, Reusing, and Recycling Code

9. Chapter 7: OOP — The Power of Objects

10. Part 3 – Software Engineering for PLCs

11. Chapter 8: Libraries — Write Once, Use Anywhere

12. Chapter 9: The SDLC — Navigating the SDLC to Create Great Code

13. Chapter 10: Advanced Coding — Using SOLID to Make Solid Code

14. Part 4 – HMIs and Alarms

15. Chapter 11: HMIs — UIs for PLCs

16. Chapter 12: Industrial Controls — User Inputs and Outputs

17. Chapter 13: Layouts — Making HMIs User-Friendly

18. Chapter 14: Alarms — Avoiding Catastrophic Issues with Alarms

19. Part 5 – Final Project and Thoughts

20. Chapter 15: Putting It All Together — The Final Project

21. Chapter 16: Distributed Control Systems, PLCs, and Networking

22. Assessments

23. Index

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Understanding debugging tools and techniques

There are many different tools and techniques that can be used to debug a program. As was discussed at the beginning of the chapter, some techniques are more sophisticated than others. It doesn’t matter which technique you use as long as you debug the software and it works as intended. As such, the following section will explore some ways to track down problems in your code.

Print debugging

The easiest way to debug a program is with print statements. Print debugging is used to isolate problems; in other words, this technique will help you find the offending code. The IEC 61131-3 doesn’t support a command that will output to a console or screen the same way languages such as Java or C++ do. However, this technique can still be used in PLC programming, and in some regards, it is a little easier to use. To demonstrate the use of print debugging, we are going to create a simple program that toggles a variable to TRUE when...