This book, now in its sixth edition, continues to be straight forward, and easy-to-read, presenting the principles of PLCs while not tying itself to one manufacturer or another. Extensive examples and chapter ending problems utilize several popular PLCs, highlighting understanding of fundamentals that can be used no matter which manufacturer. This book will help you to understand the main design characteristics, internal architecture, and operating principles of programmable logic controllers, as well as Identify safety issues with PLC systems so that they can be safely used and methods for fault diagnosis, testing, and debugging. New to This edition:. . . A new chapter 1 with a comparison of relay-controlled systems, microprocessor-controlled systems, and the programmable logic controller, with a discussion of PLC hardware and architecture, with examples from various PLC manufacturers, security, the IEC programming standard, programming devices and manufacturer's software. More detail of programming using Sequential Function Charts. Extended coverage of the sequencer. More Information on fault finding, including testing inputs and outputs with an illustration of how it is done with the PLC manufacturer's software. New case studies .