Читать книгу Programmable Logic Controllers - Su Chen Jonathon Lin - Страница 6

Preface

Programmable logic controllers (PLCs) have revolutionized the process control industry. Since their development in 1969, the functions of PLCs have extended beyond hard-wired relay replacement to math functions, data manipulation functions, proportional–integral–derivative (PID) control functions, and artificial intelligence for more sophisticated control systems. Today, every aspect of industry — from machine control to power generation to chemical process control — uses PLCs to implement the control scheme of production.

I have written this book to provide engineering students and professionals with a broad range of knowledge and skills that are essential in using PLCs to implement control schemes in various industries. The text is comprehensive in that it covers control logic design, PLC hardware and software, PLC instructions, and PLC programming.

The text is designed for flexible use so that readers can easily choose the desired depth of coverage. Chapters 1 through 5 focus on electrical control fundamentals, number systems, logic basics, Boolean algebra, and simplifying logic circuits. This group of chapters provides readers who are studying manufacturing, industrial engineering, and mechanical engineering with the necessary electrical control backgrounds to effectively learn PLCs. Chapters 6 and 7 introduce two methods of designing PLC control logics and circuits. The knowledge in these two chapters is very important for PLC programmers, yet is absent in many PLC texts. Chapters 8, 9, and 10 introduce PLC memory, file structure, discrete input and output modules, and analog input and output modules. Chapters 11 through 18 cover all important basic as well as advanced PLC programming instructions.

The text is generic in nature but also specific for Allen-Bradley SLC 500 PLCs. Readers shall be able to learn generic principles and apply them to a specific PLC model with little need for help from PLC manuals.