Chapter 12, Problem 3RQ

Program Plan Intro

Programmable Logic Controller (PLC):

• Programmable Logic Controller (PLC) is a specialized computer used in industrial segments to control machines and process.
• PLC is program that consists of a set of instructions which resembles the controlling functions needed to perform specific tasks.
• The function of PLC is similar to that of a relay and hence, in an industrial segment a relay is greatly replaced by a suitable PLC.
• When compared to general Personal Computer (PC), a PLC is available in small and tiny sizes.
• The basic architecture of a PLC consists of an input-output interface module and a small Central Processing Unit (CPU) that runs by controlling programming language.

Sequencers:

• Programmable Logic Controller (PLC) sequencer performs ON or OFF output patterns using sequencer instructions.
• The sequencer output instruction is used for controlling the output devices.
• PLC sequencer instructions are used for controlling machines which provides a stepped sequence of repeatable operations.
• It simplifies the ladder program by allowing the user to use a single or pair of instructions for performing complex operations.
• Various sequencer instructions can be programmed based on the PLC manufacturer.