Programmable Logic Controllers

Book excerpt: A text covering fundamental programmable logic controller (PLC) programming and interfacing methods. Included is a collection of sample ladder logic program segments to perform specific tasks in any PLC program such as flashers, non-standard clocks, timed counters and sequencers, flip flops (RS, D, T, JK), majority decision networks, and one-shots. Topics then move into interfacing methods, discrete sensors, linear transducers, encoders, motor controllers, PID, system safety, and pneumatics. The text can be used in any community college or university-level Engineering Technology PLC course and is also an excellent addition to an engineer's or technician's technical reference library. Readers should have a thorough understanding of fundamental dc and ac circuits, electronic devices (including thyristors), and a knowledge of college algebra and trigonometry.