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Mastering PLC Programming

You're reading from  Mastering PLC Programming

Product type Book
Published in Mar 2023
Publisher Packt
ISBN-13 9781804612880
Pages 386 pages
Edition 1st Edition
Languages
Author (1):
Mason White Mason White
Profile icon Mason White

Table of Contents (25) Chapters

Preface 1. Part 1 – An Introduction to Advanced PLC Programming
2. Chapter 1: Software Engineering for PLCs 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 24. Other Books You May Enjoy

Understanding references

A reference is a type of pointer that is more user-friendly and requires less syntax than a traditional pointer. A few big advantages of using a reference are that you do not have to use the ^ symbol, you do not have to use the ADR operator, and finally, references are type-safe.

References share many similarities with pointers, including similar syntax. As such, much like pointers, a reference must be declared. Therefore, the first step in learning how to use pointers is to understand how to declare them.

Declaring a reference variable

Declaring a reference is almost the same syntax as declaring a pointer. This can be thought of as a shorthand way of using a pointer. The only difference is that the REFERENCE keyword is used as opposed to the POINTER keyword.

This is the syntax to declare a REFERENCE variable:

<variable> : REFERENCE TO <data type>

Putting this syntax into practice, we can create a reference to an integer, as in...

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