15.4Immediate Input and Immediate Output Instructions
Chapter 16: Data Manipulation Instructions
16.1Data Structure (Bits, Words, and Files)
16.2Data Conversion Instructions
16.3Thumbwheel Switches and 7-Segment Display
16.4Data Transfer
16.5Word Transfer Instructions
16.6Bit Shift Instructions
16.7Word Shift Instructions
Chapter 17: PLC Sequencer Instructions
17.1Electromechanical Sequencers
17.2PLC Sequencer Instructions
17.3Sequencer Output (SQO) Instructions
17.4Sequencer Compare (SQC) Instructions
17.5Sequencer Load (SQL) Instructions
Chapter 18: Proportional-Integral-Derivative (PID) Control
18.1Open-Loop and Closed-Loop Control Systems
18.2On-Off Control
18.3PID Control
18.4PID Tuning
18.5PID Instruction
18.6PID and Analog I/O Scaling
18.7Using SCL Instruction
18.8A Programming Example: PID Motor Speed Control
Index
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.
I would like to thank the many people who helped to make this text possible. First, I want to thank many former students who took my PLC courses at Eastern Michigan University. Some of their creative ideas and PLC programming projects are included in many chapters. Their contributions to this text are very appreciated.
I would like to thank Jim Dodd, Robert Weinstein, Janet Romano, Cathleen Prisco, and other editing and production staff at Industrial Press for their patience and professional skills in working on this text.
I am greatly indebted to my dear wife, Grace, for her support and encouragement.
Su-Chen Jonathon Lin
PROGRAMMABLE
LOGIC
CONTROLLERS
Introduction to Programmable Logic Controllers
