Continuing the well-established tradition of its bestselling predecessors, this straight forward and easy-to-use book presents the principles of PLCs. With minimal jargon, clear explanation and simple examples, this is the book for students and professionals who need to understand and get up and running with PLCs in their studies or work. The book is not device specific, meaning it ensures maximum applicability to readers. Usability and understanding is aided by extensive examples and end-of-chapter problems that utilize several popular PLCs. This edition has been enhanced with new material on combinational and sequential logic, I/Os, protocols and networking.