Programmable Logic Controllers, Fifth Edition

Book Preface

Technological advances in recent years have resulted in the development of the programmable logic controller (PLC) and a consequential revolution of control engineering.

This book, an introduction to PLCs, aims to ease the tasks of practicing engineers coming into contact with PLCs for the first time. It also provides a basic course for students in curricula such as the English technicians’ courses for Nationals and Higher Nationals in Engineering, giving full syllabus coverage of the National and Higher National in Engineering units, company training programs, and serving as an introduction for first-year undergraduate courses in engineering.

The book addresses the problem of various programmable control manufacturers using different nomenclature and program forms by describing the principles involved and illustrating them with examples from a range of manufacturers. The text includes:
• The basic architecture of PLCs and the characteristics of commonly used input and outputs to such systems
• A discussion of the number systems: denary, binary, octal, hexadecimal, and BCD
• A painstaking methodical introduction, with many illustrations, describing how to program PLCs, whatever the manufacturer, and how to use internal relays, timers, counters, shift registers, sequencers, and data-handling facilities
• Consideration of the standards given by IEC 1131-3 and the programming methods of ladder, functional block diagram, instruction list, structured text, and sequential function chart
• Many worked examples, multiple-choice questions, and problems to assist the reader in developing the skills necessary to write programs for programmable logic controllers, with answers to all multiple-choice questions and problems given at the end of the book