Chapter 5

Ladder and Functional Block Programming

Abstract

This chapter is an introduction to programming a PLC using ladder diagrams and functional block diagrams and their uses to represent basic switching operations involving the logic functions AND, OR, EXCLUSIVE OR, NAND and NOR, as well as latching. Programs involving such operations are developed.

Keywords

Ladder diagram and functional block programming

Programs for microprocessor-based systems have to be loaded in machine code, a sequence of binary code numbers to represent the program instructions. However, assembly language based on the use of mnemonics can be used; for example, LD is used to indicate the operation required to load the data that follows the LD, and a computer program ...

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