Mechatronics: Electronic Control Systems In Mechanical and Electrical Engineering, 7th Edition by Pearson

Chapter fourteen

Programmable logic controllers

Objectives

The objectives of this chapter are that, after studying it, the reader should be able to:

• Describe the basic structure of PLCs and their operation.
• Develop ladder programs for a PLC involving logic functions, latching, internal relays and sequencing.
• Develop programs involving timers, counters, shift registers, master relays, jumps and data handling.

14.1 Programmable logic controller

A programmable logic controller (PLC) is a device that uses a programmable memory to store instructions and to implement functions such as logic, sequencing, timing, counting and arithmetic in order to control machines and processes and has been specifically designed to make programming easy. The ...