This is an introductory text that explores many aspects of PLCs in an easy-to-understand manner. The text organization begins with basic concepts and progresses to system level applications. Specifically, the text provides an overview of programmable logic controllers (PLCs), which includes PLC selection, components, and communication. It also teches students how to create relay logic diagrams, utilize PLC instructions to program PLCs, and troubleshoot and service PLCs. CD-ROM included.