iii Preface Programmable Logic Controllers: Hardware and Programming is an introductory text that explores many aspects of PLCs in an easy-to-understand manner. The key concepts of PLCs are discussed using a comprehensive approach to enhance learning. The text organization begins with basic concepts and progresses to system level applications. Applications, testing procedures, and operational aspects of PLC equipment and systems are discussed. This textbook emphasizes the PLC’s practical use in industry. The programmable logic controller was first introduced in the automotive industry in the late 1960s. Today, PLCs are found throughout all manufacturing industries and are increasingly found in commercial building automation systems. Knowledge of selecting, wiring, and programming PLCs is required in many career fields, including industrial controls, automation engineering, and industrial maintenance. This textbook describes the most common programmable logic controller functions and provides examples using the Allen-Bradley Small Logic Controller (SLC 500) series. There are a few software simulators for the SLC 500 for your choosing. A quick web search can yield results from a variety of suppliers and prices. The last chapter of the text discusses the next generation RSLogix 5000 software. PLC theory and PLC selection for various applications are explained. PLC wiring and programming are also covered with numerous examples. About the Author Max Rabiee earned his PhD in electrical engineering from the University of Kentucky. He has taught electrical engineering (EE) and electrical/computer engineering technology (ECET) courses for over 25 years. Dr. Rabiee is a registered professional engineer (since 1988) who worked as a control engineer for several years. He was a senior electrical engineer for over four years in charge of medium and large industrial control projects. Dr. Rabiee is a member of the American Society of Engineering Education (ASEE), the Institute of Electrical and Electronics Engineers (IEEE), the Association of Technology, Management, and Applied Engineering (ATMAE), the Eta Kappa Nu Electrical Engineering Honor Society, and the Tau Beta Pi Engineering Honor Society.