Programmable logic controllers (PLCs) are extensively used in industry to perform automation tasks, with manufacturers offering a variety of PLCs that differ in functions, program memories, and the number of inputs/outputs (I/O). Not surprisingly, the design and implementation of these PLCs have long been a secret of manufacturers. Unveiling the mysteries of PLC technology, Building a Programmable Logic Controller with PIC16F648A Microcontroller explains how to design and use a PIC16F648A-microcontroller-based PLC.
The author first described a microcontroller-based implementation of a PLC in a series of articles published in Electronics World magazine between 2008 and 2010. This book is based on an improved version of the project, including:
Updates to the hardware configuration, with a smaller CPU board and two I/O extension boards that now support 16 inputs and 16 outputs instead of 8
An increased clock frequency of 20 MHz
Improvements to several macros
Flowcharts to help you understand the macros (functions)
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