2 introduction to automation

7/27/2019 2 Introduction to Automation

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Introduction to AutomationBasic Elements of an Automated SystemAdvanced Automation Functions

Level of Automation


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Introduction

Automation is technology by which a process or procedure is accomplished

without human assistanceAutomation is implemented using a

program of instruction combined with acontrol system that executes the instructionPower is required to drive the process andto operate the program and control system


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Basic Element of an Automated

SystemAn automated system consists of three basic

elements

Power to accomplish the process andoperate the systemA program of instruction to direct the

processA control system to actuate the instructions


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Elements of Automated System

Power

Program of

instructions

Control

systemProcess


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Power to accomplish the

Automated ProcessAdvantage of Electrical Power

Widely available at moderate cost

Can be readily converted to alternativeenergy form like mechanical, thermal, light,acoustic, hydraulic & pneumaticAt a low level can be used to accomplishfunction like signal transmission,information processing, data storageCan be storage in long-live batteries


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Power for the Process

In production, the term of process refers tothe manufacturing operation that is

performed on a work unit. Most of the power in manufacturing is thermal,electrical, and mechanicalThe power source is often converted fromelectricity


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Common Manufacturing Process

and Their Power RequirementsProcess power formCasting thermalEDM electricalForging mechanicalHeat treating thermalInjection molding thermal & mechanical

Machining mechanicalPunching & blanking mechanicalWelding thermal


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Additional process in manufacturing

Loading and unloading the work unitMaterial transport between operations


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Power for Automation

Controller unit Modern industrial controller are based on digital

computer

Power to actuate the control signals The command send by the control unit are carried out

by mean of electromechanical devices (switch, motor,

actuator)Data acquisition and information processing Data must be collected from process and used as input

to the control algorithm. This data acquisition and

record keeping function require power


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Program of Instructions

The actions performed by an automated process are defined by a program of instructionsThese processing steps are performedduring a work cycleA new part is completed during each work

cycle (sometimes more than one part produced during the work cycle ex multicavity plastic part)


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Work cycle programs

In the simple automated process the work cycle consist of single step process

In the more complicated system typically: Load the part into the production machine Perform the process

Unload the partDuring each step there are one or moreactivities or more process parameter


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Process parameters

Process parameters are inputs to the process:

Temperature setting Coordinate axis value in positioning system Valve opened/closed in a fluid flow system

Motor on/off


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Feature of the work Cycle

The number and sequence of processingsteps

Process parameter changes in each step


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Decision-Making in the

Programmed Work CycleOperator interaction Ex automated engraving operation (operator may have to enter

the alphanumeric character)

Difference part or product style processed by the system The automated system is programmed to perform different work cycle on the different part or product

Ex industrial robot for spot welding (often designed to builddifferent body style)

Variations in the starting work unit The starting work units are not consistent Ex starting work unit machining operation for sand casting

material


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Summary the features of work

cycle program Number of steps in work cycle Load, process and unload

Manual participation in the work cycleProcess parameter Operator interaction

Variations in part or product styleVariations in starting work units


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Control System

The control elemen of the automatedsystem executes the program of

instructionsThe control in an automated system Open loop control system

Closed loop control system or a feedback control system


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Open loop

Conditions in open loop system The action performed by the control system

are simple

The actuating function is very reliable Any reaction opposing the actuator are smallenough to have no effect on the actuating

Input parameter

controller actuator process Outputvariable


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Close loopInput

parameter controller actuator process Output

variable

Feedback sensor


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Advanced Automation Functions

In additional, an automated system may becapable of executing advanced functions

that are not specific to a particular work unitFunction

safety monitoring Maintenance and repair diagnostic Error detection and recovery


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safety monitoring

Reason To protect human workers in the vicinity of

the system To protect the equipment associated with the

system

Safety monitoring means more than theconventional safety measures taken in amanufacturing operation


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Possible responses to various

hazardsCompletely stopping the automated systemSounding an alarm

Reducing the operating speed of the processTaking corrective actions to recover from

the safety violation


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Maintenance and repair diagnostic

Statues monitoringFailure diagnostics

Recommendation of repair procedure


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Levels of AutomationEnterprise Level

Plant Level

Cell or System Level

Machine Level

Device Level

Corporate InformationSystem

Production System

Manufacturing systemgroup of machine

Individual Level

Sensor, actuators, other hardware element

Flow of data


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Device Level

It includes the actuators, sensors, and other hardware components that comprise the

machine levelThe device are combined into theindividual control loops of the machineFor example the feed back control loop for one axis of a CNC machine


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Machine Level

Hardware in the device level is assembledinto individual machine

CNC machine tools and similar productionequipment, industrial robots, power conveyor, and automated guided vehicleControl level at this level include

performing the sequence of steps in the program of instructions in the correct order and making sure that steps is properlyexecuted


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Cell or System Level

A manufacturing cell or system is a groupof machines or work stations connectedand supported by a material handlingsystem, computer, and other equipmentappropriated to the manufacturing processConsist of production lines, partdispatching, machine loading, materialhandling system, coordinating amongmachines, colecting data, and evaluatinginspection data


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Plant Level

This is the factory or production systemslevel

Consist of order processing, process planning, inventory control, purchasing,MRP, shop floor control, and qualitycontrol


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Enterprise Level

Consist of the corporate informationsystem

It is concerned with all the functipnnecessary to manage the companyIncludes marketing, sales, accounting,design, research, aggregate planning, andmaster production scheduling

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