Chapter 10

Counters

Abstract

This chapter shows how counters and up- and down-counters can be used in programs, also sequencers. Programs involving such operations are developed.

Keywords

counters

sequencers

Counters are provided as built-in elements in PLCs and allow the number of occurrences of input signals to be counted. Some uses might include where items have to be counted as they pass along a conveyor belt, the number of revolutions of a shaft, or perhaps the number of people passing through a door. This chapter describes how such counters can be programmed.

10.1 Forms of Counter

A counter is set to some preset number value and, when this value of input pulses has been received, it will operate its contacts. Normally open contacts ...

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