Automatic horn housing conveying and positioning system

7/27/2019 Automatic horn housing conveying and positioning system

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AUTOMATIC HORN HOUSING

CONVEYING AND POSITIONING

SYSTEM

A PROJECT REPORT

Submitted by

R.MOHAN PRAKASH 090112112023

P.TATAVARATHARAJAPERUMAL 100412112014

I n partial f ul fi llment for the award of the degree

Of

BACHELOR OF ENGINEERING

IN

MECHATRONICS ENGINEERING

MAHARAJA ENGINEERING COLLEGE, AVINASHI

ANNA UNIVERSITY :: CHENNAI 600 025

APRIL 2013
http://www.google.co.in/imgres?imgurl=http://www.maharaja.in/mec/images/logo.gif&imgrefurl=http://www.maharaja.in/mec/index.html&h=93&w=145&sz=6&tbnid=f4hjpOHewHg8iM:&tbnh=74&tbnw=116&prev=/search?q=maharaja+engineering+college+logo&tbm=isch&tbo=u&zoom=1&q=maharaja+engineering+college+logo&usg=__4k8bHasaYOpQs115gWoYbifWS8k=&docid=3mUBZE8lXE3NaM&hl=en&sa=X&ei=bnN9UKinHM3MrQeyrYGYCQ&ved=0CCsQ9QEwAg&dur=2657


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ANNA UNIVERSITY :: CHENNAI 600 025

BONAFIDE CERTIFICATE

Certified that this project report AUTOMATIC HORN HOUSING

POSITIONER AND THREAD INSPECTION SYSTEM is the bonafide

work of MOHAN PRAKASH.R, TATAVARATHARAJAPERUMAL.P

who carried out the project work under my supervision.

SIGNATURE SIGNATURE

Mr.L.FEROZ ALI B.E., (M.E), Mr.T.VELUMANI M.E., (Ph.D),

SUPERVISOR HEAD OF THE DEPARTMENT

Department of Mechatronics Engineering Department of Mechatronics Engineering

Maharaja Engineering college Maharaja Engineering college

Avinashi-641654 Avinashi-641654

INTERNAL EXAMINER EXTERNAL EXAMINER


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ACKNOWLEDGEMENT

Our heartfelt and sincere thanks goes to our beloved and honorable chairman

Thiru K.PARAMASIVAM B.Sc., for having provided us with all necessary

infrastructure and other facilities. Our special thanks to our beloved

correspondent Thiru P.SATHIYAMOORTHY B.E., MBA., M.S., for his

extensive support to successfully complete this project.

We extend our sincere gratitude to Mr. T.VELUMANI M.E., (Ph.D), Head

of the department, Department of Mechatronics Engineering, Maharaja

Engineering College, Avinashi for extending all possible help for this work.

We heartily thank our internal project guide Mr. L. FEROZ ALI B.E.,

(M.E), Lecturer, Department of Mechatronics Engineering for his valuable

guidance in making this project to grant success.

We respect and thank to Dr. KAVIDASAN, Director - HR giving an

opportunity to do the project work in Roots Industries India Ltd., and providing

us all support and guidance which made us complete the project on time.

We owe our profound gratitude to our project guide Mr.M.Vijayakumar

Head - Facility Development and Automation who took keen interest on our

project work and guided us all along by providing all the necessary information

for developing an innovative system.

Last but not least we extend our heartfelt thanks to our beloved parents

and the friends who has always been an integral part in helping us through times

and making our project a Herculean success.


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ABSTRACT

This project we proposed is mainly focused on automation as well as

quality improvement. Basically this proposed system is controlled and

automated by PLC. Major feed forward part of project is LDR; based on the

feedback pulses the Auto-positioning table will orient the horn housings.

This project assures the manpower elimination of housing manufacturing

process. The conveyance of housing from other machines to riveting

operation machine is done by belt conveyor setup with the help of vacuum

gripper-I housings are located on auto-positioning system. The Holes present

in housing are the reference of this system, based on the light source

intensity passed through holes apparently switch the LDRs and make the

exact orientation by stopping the prime moving equipment. Further the

vacuum gripper-II will convey the housings to Auto indexing fixtures.

Obviously the machine will perform the specified task (riveting).The

automatic positioning of housing is chosen to eliminate the manual feeding

of housings and also enhance the flawless production strategy.


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COMPANY PROFILE

INTRODUCTION

Roots Industries India Ltd is a leading manufacturer of Automotive

HORNS in India and the 11th largest Horn Manufacturing Company in the

world. Headquartered in Coimbatore - India, ROOTS has been a dominant

player in the manufacture of Horns and other products like CASTINGS

and INDUSTRIAL CLEANING MACHINES. Since its establishment in 1970,

ROOTS has had a vision and commitment to produce and deliver quality

products adhering to International Standards.

With a strong innovative base and commitment to Quality, Roots Industries

India Ltd has occupied a key position in both international and domestic market

as suppliers to leading OEMs and after market. Similar to products, Roots has

leading edge over competitors on strong quality system base. Now, RIL is the

first Indian Company and first horn manufacturing company in the world to get

ISO/TS 16949 certification based on effective implementation of QS 9000 and

VDA 6.1 system requirement earlier. Roots' vision is to become a world class

company manufacturing world class product, excelling in human relation.

CORPORATE

Roots' single minded pursuit of enhancing the quality of life has led to many

other diversifications. Roots, today, is a multifaceted corporate entity with


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interests in automobile accessories, cleaning equipment, castings, precision

tools, hi-tech engineering services, healthcare and education.

In a dynamic world that is driven by technology, a successful presence

depends on the way you mould that technology to fit popular

needs. Indigenous talent, a daring attitude, courage to accept and learn new

things and the simple spark of an idea. That is the genesis of ROOTS.

MILESTONES

1970 Promotes American Auto Service for manufacture of Electric

Horns.

1972 First to manufacture Servo Brakes for Light Motor Vehicles.

1984 Roots Auto Products Private Limited was established to

manufacture Air Horns. Die Casting Unit commences commercial

operations.

1988 Polycraft, a unit for Plastic Injection Moulding was established.

1990 Roots Industries India Ltd takes over Electric Horn business.

1992 RMCL enters into Techno-Financial collaboration with M/s.

Hako Werke GmbH, Germany.

1992 Roots Industries India Ltd obtains the National Certification -

ISI mark of quality.


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1994 Production of floor cleaning equipment commences.

Roots Industries India Ltd wins American International Quality

Award.

1999 Becomes the first horn manufacturer in Asia to obtain QS 9000

2000 Becomes the first horn manufacturer in Asia to obtain VDA 6.1

and the first in the world to win ISO / TS 16949

2000 The first to introduce digitally controlled air horns and low

frequency, low decibel irritation free Jumbo Air Horns.

2003 Roots Industries India Ltd., Horn Division is accredited with ISO

14001: 1996

2003 Roots Industries India Ltd., upgraded its ISO / TS 16949 from

1999 version to 2002 version

2004 Roots Industries India Ltd (RIL) opens its 100% exclusive Export

Oriented Unit at their Horn Division, Thoppampatti, Coimbatore to

cater the needs of Ford North America.

2004 RIL's EOU commences its supplies to Ford, North America

2004 Roots Multiclean Limited (RMCL) inaugurates its 100% EOU

Plant at Kovilpalayam, Coimbatore

2004 Roots Cast Private Limited (RCPL) inaugurates its Unit II at

Arugampalayam, Coimbatore


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2004 Roots Auto Products Pvt Ltd (RAPPL) expands with its

Machining Division at Arugampalayam, Coimbatore

2004 RIL successfully launches its Malaysian Plant

2004 The group company American Auto Service is accredited with

ISO 9001: 2000

2005 Roots Industries India Ltd., is certified with MS 9000, a pre-

requisite for Q1 award for Ford Automotive Operations Suppliers.

Focus on Systems and Processes

2005 Roots Metrology & Testing Laboratory has been accredited by

National Accreditation Board for testing & calibration in the field of

Mechanical Linear & Angular

2005 Roots Industries India Ltd., is awarded Q1 by Ford Motor

Company

2005 Roots Industries India Ltd., Horn Division upgraded its ISO:

14001 from 1996 version to 2004 version

VISION

We will stand technologically ahead of others to deliver world-classinnovative products useful to our customers. We will rather lose our business

than our customers' satisfaction. It is our aim that the customer should get the

best value for his money.


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Every member of our company will have decent living standards. We care

deeply for our families, for our environment and our society. We promise to pay

back in full measure to the society by way of selfless and unstinted service.

ROOTS GROUP OF COMPANIES

Roots Industries India Ltd ElectricHorns

Roots Auto Products Private Limited Air Horns, Switches & Controllers

Roots Multiclean Limited Cleaning Machines

Roots Cast Private Limited Aluminium & Zinc Pressure Die Cast

Roots Precision Products Dies, Tools, Jigs & Fixtures

Roots Metrology Laboratory Instrument Calibration, Quality

System, Consultancy

Roots Polycraft Plastic components

R K Nature Cure Home Nature Cure Therapy, Yoga &

Massages

Satchidananda Jothi Nikethan International School

Integral Yoga Institute Yoga and Meditation

Roots Industries Malaysia Sdn. Bhd. Electric Horns
http://www.rootsindia.com/html/ril.htmlhttp://www.rootsindia.com/html/rappl.htmlhttp://www.rmclindia.com/http://www.rootsindia.com/html/rcpl.htmlhttp://www.rootsindia.com/html/rpp.htmlhttp://www.rootsindia.com/html/metrology.htmlhttp://www.rootsindia.com/html/pc.htmlhttp://www.rootsindia.com/html/rknch.htmlhttp://www.rootsindia.com/html/sjnms.htmlhttp://www.integralyogaindia.org/http://www.integralyogaindia.org/http://www.rootsindia.com/html/sjnms.htmlhttp://www.rootsindia.com/html/rknch.htmlhttp://www.rootsindia.com/html/pc.htmlhttp://www.rootsindia.com/html/metrology.htmlhttp://www.rootsindia.com/html/rpp.htmlhttp://www.rootsindia.com/html/rcpl.htmlhttp://www.rmclindia.com/http://www.rootsindia.com/html/rappl.htmlhttp://www.rootsindia.com/html/ril.html


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CHAPTER 1

INTRODUCTION

1.1 OBJECTIVE

The objective of the project is to make an automatic system for conveying,

handling and feeding the semi-finished goods in the press shop. This project we

had chosen is to eliminate the human resources as well as improves the

efficiency, quality of parts being produced in shop floor. Thus turning up the

conventional process into an automatic way.

1.2 PRESS SHOP

The division which converts the raw materials such as sheet metal plates

and steel rolls into the Horn Housings, Diaphragms, Vent shields, Point plates,

Mounting brackets, Tone disc, Point holders, Clamps.

The Press shop contains both automatic and conventional kind of

machineries for producing the goods. Further sub-divisions brief about the

machine tools, materials, process and parts.

1.2.1 TYPES OF MACHINES

Power press Hydraulic press Feeder press Pneumatic press Lathe press Feeder press with multiple operations


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1.2.2 TYPES OF TOOLS

Conventional tool Progressive tool Compound tool

1.2.3 TYPES OF PROCESS

Blanking Draw RestrikingNotching Trimming Forming Embossing Flanging Edge Chamfering

Rib forming Collar draw Flattering / Planishing Turning Riveting Bending Lancing Knurling Coining Stress Relieving


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1.2.3.1 COMBINED PROCESSES

Piercing and Blanking Piercing and Blanking and Notching Piercing and Blanking and Bending Piercing and Blanking and Cropping SCR Riveting and Planishing and Lancing SCR Riveting and Planishing and Lancing and Flanging Edge Chamfering and Lancing Hour Glass Cutting Draw I, Draw II, Draw III and Restrike Collar draw, Piercing, Lettering and Trimming Blanking and Forming Forming and Flanging Piercing, Lettering and Blanking

1.2.4 TYPES OF RAW MATERIALS

Aluminium Zinc Galvanised Steel Cold rolled Carbon Steel Spring Steel Stainless Steel

1.2.5 TYPES OF PARTS

Housing with SCR assembly Housing with E-Core assembly Diaphragm Tone disc


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Point plate Point holder Grill Keeper ring Mounting bracket Mounting bracket assembly Horn cover Connector Condenser bracket Clamp

1.2.6 PROCESS SEQUENCE OF HOUSING PRODUCTION

The below flow chart describes about the step by step process of

manufacturing the horn housings.

Raw material feeding (Steel

plate roll)

Internal Storage

Blanking of steel plate

Drawing I, II


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Restrike

Piercing

A

A

Notching

Flattering/ Planishing

Riveting

Manual

feeding

By

labour


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The projected system plays at the stage of manual feeding block of the flow

chart.

Bending & Lancing

Lettering

FG Container


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CHAPTER 2

SYSTEM ANALYSIS

2.1 EXISTING SYSTEM

Presently, the Horn Housing production process utilizes the Man power in

the process of conveying/loading the Horn housing at the press shop of the

industry. The worker loads the components into auto indexing fixtures at regular

intervals for the process to be proceeded. Currently the goods are made to fallinto a trolley, a mass material holding steel box from previous machine. The

manual labour moves these components from one machine to another to

perform successive manufacturing processes. The Containers are moved by the

forklifts. The worker will get himself seated near the machine for the whole shift

or until all the components are loaded into the machine. It is to be noticed that

most of the processes are done automatically, yet this work is carried out usinglabour.


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Fig 2.1 Existing Manual System

2.2 DRAWBACKS OF EXISTING SYSTEM

The existing system has a numerous drawbacks as listed below:

The manual feeding of the housing components onto the Auto Indexingfixture is found to be physically more difficult for the workers.

The loading of these components when done conventionally, is timeconsuming which leads to increase in the cycle time of production. Thus

affecting the production rate.

The movement of the semi finished parts from one machine to another alsoconsumes some amount of time.

The mishandling of the horn housing may also take place depending uponthe labours cooperation.


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The unnecessary utilization of human source is found in this process whichis considered as an excess labour cost.

Chance of Erratic loading and irregularities due to the fatigue of humanresource.

2.3 PROPOSED SYSTEM

To overcome the above mentioned problems, automated way of approach

for the process is suggested under the name of Automatic horn housing

conveying and positioning system. This approach has a lot of features when

compared to the existing system.

Fig 2.2 Pictorial representation of proposed system


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The proposed system has the major components such as

Motor Driven Belt Conveyor Pneumatic operated Vacuum End Effector AutoOrientation detection fixture Light Dependent resistors(LDR) Programmable Logic Controller(PLC) Light source

Each of the components plays the major role in this automated system, Each and

every component will performs the specified task with optimistic resolution and

repeatability.

2.3.1 ADVANTAGES OF PROPOSED SYSTEM

Manpower elimination Higher productivity Greater Accuracy Independent Control system Lesser labour intensive Reduction in labour cost Economic facility development


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CHAPTER 3

BASIC OPERATION OF AUTO-POSITIONER

3.1 ACQUISITION AND CONVEYANCE OF HOUSINGS

The proposed system is has a conveyor belt which operates in variable speed

and convenient to haul items from one point to another. It is a mechanical loop,

usually made of rubber that goes around its mechanism for a continuous cycle.

Fig 3.1 Conveyor Belt setup

The conveyor belts are motorized. Which connects the two machines and

holds the semi finished horn housings. Basically it is operated by Compact

Brushless DC gear motor.


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3.2 PLACING OF HOUSINGS INTO AUTO ORIENT FIXTURE

There is a manipulator placed at the end of this lengthy conveyor belt. The

semi finished part is picked up by the automated-pneumatic controlled end

effector. The gripper has an optical proximity sensor head that senses the arrival or

presence of component in the conveyor belt.

Fig 3.2 Picking up of Housing from conveyor

The gripper end has a vacuum cup for holding up the part, so that if the

component arrives even upside down, it can be easily handled without any

distractions. Further the end effector displaces the housing with the help of motor

operated slide-way projection. Finally the housing located at the exact span andheight of the auto-orient fixture.


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3.3 OBTAINING OF REQUIRED ORIENTATION

The Housing placed after the Auto Orientation fixture, the setup will rotated

by DC motor.

Fig 3.3 Typical sketch of Auto positioning system

Simultaneously the light source get switched ON which is located above this

fixture. There are two reference holes in housing which helps to make the exact

positioning. The Light Dependant Resistor (LDR) is placed under the Auto

Orientation fixture below those reference holes.

Those photo diodes will make the motor of the fixture table to rotate until

both the photo diodes receive the illumination through the reference holes from

light source. Thus the motor will stopped immediately, this control action

performed by a Programmable Logic Controller (PLC).


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3.4 LOCATION OF HOUSINGS INTO AUTO INDEXING FIXTURE

There is an Auto Indexing fixture basically found to be attached to this

machine have capacity to hold four components. The fixtures profile off-set to 90

angle to one another and the table is circular in shape.

Fig 3.4 Picking Operation

At the end of exact orientation process both the manipulators are actuated by

at same time, End effector II grasps the oriented housing and placed over the auto

indexing fixture. Mean time End effector I picks up the new component from the

conveyor and placed on the Auto-orientation fixture, further the process repeated

as cyclic manner.


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CHAPTER 4

OVERVIEW OF COMPONENTS

4.1 INTRODUCTION

The Block diagram shows the various components of the Automatic Horn

Housing conveying and positioning system.

Fig 4.1 Block Diagram of proposed system

PROGRAMMABLE

LOGIC

CONTROLLER

(PLC)

LDR (Light

Dependent

Resistor)

InductiveProximity

Sensor

Optical

proximity

sensor

Conveyor

Motor

Manipulator

Actuators

Orientation

fixture motor

Power source

Light

source


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The Project Automatic horn housing conveying and positioning system

consists of a mechanical chassis that consists of several Mechanical set ups and

Electrical components. The basic information of all these components and set ups

are mentioned in this chapter. Their images are also included along with their

definition. The workings of individual parts are also specified under the same list.

4.2 MECHANICAL ELEMENT

The mechanical element here is the conveyor that is set up in between the

two processing machines that produce Horn Housing.

4.2.1 CONVEYOR

A conveyor system is a common piece of mechanical handling equipment

that moves materials from one location to another. Conveyors here are especially

useful in involving the transportation of horn housing materials. Conveyor systems

allow quick and efficient transportation for a wide variety of materials which make

them very popular in Material handling. They move the products in a timely

fashion. A conveyor system that is designed properly will last a long time with

proper maintenance.

4.2.1.1 BELT TYPE CONVEYOR

Choosing the right conveyor type for the right system design is a major

factor in all aspects. In our project, the belt type conveyor is chosen. A beltconveyor consists of two or more pulleys, with a continuous loop of material - the

conveyor belt - that rotates about them. One or both of the pulleys are powered,

moving the belt and the material on the belt forward. The powered pulley is called

the drive pulley while the unpowered pulley is called the idler. The belt is made of

Rubber with a flat metal bed such that they can handle irregular bottom surfaces.
http://en.wikipedia.org/wiki/Pulleyhttp://en.wikipedia.org/wiki/Pulley


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They are of many layers to provide linear strength. The conveyor belt is motor

driven and is controlled by computer pulse signals.

Fig 4.2 Belt Conveyor

4.2.1.2 SPECIFICATIONS

The belt conveyors used for this system are subjected to following

specifications.

Belt width110 mm Belt Length / Power3.2/0.6 (m/kW) Belt Speed0.005 (m/s) Capacity2-3 (t/h) Angle of Conveyor Belt0degree


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4.3 ELECTRICAL COMPONENTS

The Electrical components are used to perform the control actions and alsoensure the proper functioning of all the mechanical elements of entire system.

4.3.1 LIGHT DEPENDANT RESISTOR

Fig 4.3 Light Dependant Resistor with Label

A Light Dependant Resistor or Photo Resistor is a resistor whose resistance

decreases with increase in light intensity. In other words, it exhibits Photo

Conductivity. A photo resistor is made of a high resistance semiconductor. If light

falling on the device is of high enough frequency, photons absorbed by the

semiconductor give bound electrons enough energy to jump into the conduction

band. The resulting free electron (and its holepartner) conduct electricity, thereby

lowering resistance. Photo resistors are basically photocells. Which is act as

feedback element as well as input signal of the PLC.
http://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Semiconductor


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4.3.2 MOTOR

The Automatic positioning system needs three motors to perform the

specified task.

They are as follows

Brushless DC Motor (Conveyor motor) High Torque DC Gear Motor (Auto orientation motor) DC Servo Motor (End effectors actuation motor)

A DC motor is a mechanically commutated electric motorpowered

from direct current (DC). The stator is stationary in space by definition and

therefore so is its current. The current in the rotor is switched by the commutatorto

also be stationary in space. This is how the relative angle between the stator and

rotor magnetic flux is maintained near 90 degrees, which generates the maximum

torque.

Fig 4.4 DC Motor
http://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Electric_motor


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The speed of a DC motor can be controlled by changing the voltage applied

to the armature or by changing the field current. The introduction of variable

resistance in the armature circuit or field circuit allowed speed control. Here, DC

motors are controlled by power electronics systems called DC drives. They drive

the Auto Orientation fixture until LDR responds to Light.

4.3.3 LIGHT SOURCE

In this project we are about to use Halogen Lamp as light source to operate

LDR. A halogen lamp, also known as a tungsten halogen lamp or quartz iodine

lamp, is an incandescent lamp that has a small amount of a halogen such

as iodine orbromine added. The combination of the halogen gas and

the tungsten filament produces a halogen cycle chemical reaction which re-

deposits evaporated tungsten back on the filament, increasing its life and

Fig 4.5 Halogen Lamp
http://en.wikipedia.org/wiki/Power_electronicshttp://en.wikipedia.org/wiki/Incandescent_light_bulbhttp://en.wikipedia.org/wiki/Halogenhttp://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Brominehttp://en.wikipedia.org/wiki/Tungstenhttp://en.wikipedia.org/wiki/Tungstenhttp://en.wikipedia.org/wiki/Brominehttp://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Halogenhttp://en.wikipedia.org/wiki/Incandescent_light_bulbhttp://en.wikipedia.org/wiki/Power_electronics


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Maintaining the clarity of the envelope. Because of this, a halogen lamp can be

operated at a higher temperature than a standard gas-filled lamp of similar power

and operating life, producing light of a higherluminous efficacy and colour

temperature. The small size of halogen lamps permits their use in compact optical

systems for illumination. The light output is reported as proportional to . It

produces a continuous spectrum of light, from near ultraviolet to deep into the

infrared.

4.3.3.1 HANDLING PRECAUTIONS

Any surface contamination, notably the oil from human fingertips, can

damage the quartz envelope when it is heated. Contaminants will create a hot spot

on the bulb surface when the lamp is turned on. This extreme, localized heat causes

the quartz to change from its vitreous form into a weaker, crystalline form that

leaks gas. This weakening may also cause the bulb to form a bubble, weakening it

and leading to its explosion.

Consequently, manufacturers recommend that quartz lamps should be

handled without touching the clear quartz, either by using a clean paper towel or

carefully holding the porcelain base. If the quartz is contaminated in any way, it

must be thoroughly cleaned with alcohol and dried before use.

4.3.4 PNEUMATIC ACTUATORS

A pneumatic actuator converts energy (typically in the form ofcompressed

air) into mechanical motion. The motion here is semi rotary, for the type ofoperation. A Pneumatic actuator mainly consists of a piston, a cylinder, and valves

or ports. The piston is covered by a diaphragm, or seal, which keeps the air in the

upper portion of the cylinder, allowing air pressure to force the diaphragm
http://en.wikipedia.org/wiki/Luminous_efficacyhttp://en.wikipedia.org/wiki/Color_temperaturehttp://en.wikipedia.org/wiki/Color_temperaturehttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Crystallinehttp://en.wikipedia.org/wiki/Compressed_airhttp://en.wikipedia.org/wiki/Compressed_airhttp://en.wikipedia.org/wiki/Diaphragm_(mechanical_device)http://en.wikipedia.org/wiki/Diaphragm_(mechanical_device)http://en.wikipedia.org/wiki/Compressed_airhttp://en.wikipedia.org/wiki/Compressed_airhttp://en.wikipedia.org/wiki/Crystallinehttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Color_temperaturehttp://en.wikipedia.org/wiki/Color_temperaturehttp://en.wikipedia.org/wiki/Luminous_efficacy


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downward, moving the piston underneath, which in turn moves the valve stem,

which is linked to the internal parts of the actuator.

The system consist of following components

Steel Guide ways (Confine the Straight motions) Pneumatic cylinders (Propel the manipulators) Vacuum operated End Effectors (Grasp the housings)

Fig 4.6 Pneumatic Actuator with Vacuum Gripper

Pneumatic actuators may only have one spot for a signal input, top or

bottom, depending on action required. Having a larger piston can also be good if

air supply is low, allowing the same forces with less input. Valves input pressure is

the "control signal." There are two grippers as one to pick and place the object

from Conveyor belt to Auto Orientation fixture respectively. Another gripper is

also interlinked with previous one to pick and place the object from Auto

Orientation to Auto Indexing fixture respectively.
http://en.wikipedia.org/wiki/Valve#Stemhttp://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Valve#Stem


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4.3.5 SENSORS

Fig 4.7 Proximity Sensor

A sensor is a device which receives and responds to a signal when touched.

A sensor (also called detector) is a converterthat measures a physical quantity and

converts it into a signal which can be read by an observer or by an electronic

instrument. Sensors are designed to have a small effect on what is measured.
http://en.wikipedia.org/wiki/Energy_conversionhttp://en.wikipedia.org/wiki/Physical_quantityhttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Physical_quantityhttp://en.wikipedia.org/wiki/Energy_conversion


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Fig 4.8 Sensor Interface in Auto Positioning system

In this project, the sensors are used in the belt conveyors for noticing the

arrival of components near the Auto Orientation fixture, which is a Inductiveproximity sensor. At the end of Vacuum gripper head, there is a optical proximity

sensor placed to pick up the component correctly. Thus, two kind of sensors are

used.

The sensors implemented in this project has following advantages:

Is sensitive to the measured property only Is insensitive to any other property likely to be encountered in its application Does not influence the measured property.


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CHAPTER 5

MOTORS AND ACTUATORS

5.1 INTRODUCTION

In this project, the conveyor pulley is driven by the Brushless DC motor.

Brushless DC electric motor (BLDC motors) also known as electronically

commutated motors (EC motors) are synchronous motors which are powered by a

DC electric source via an integrated inverter/switching power supply, which

produces an AC electric signal to drive the motor (AC with a caveat alternating

current often implies a sinusoidal waveform; a better term would be bi-directional

current with no restriction on waveform); additional sensors and electronics control

the inverter output amplitude and waveform (and therefore percent of DC bus

usage/efficiency) and frequency (i.e. rotor speed).

Fig 5.1 Brushless DC Motor

5.2 BRUSHLESS DC MOTOR

The motor part of a brushless motor is often a permanent magnet

synchronous motor, but can also be a switched reluctance motor, orinduction

motor. Brushless motors may be described as stepper motors; however, the
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term stepper motor tends to be used for motors that are designed specifically to be

operated in a mode where they are frequently stopped with the rotor in a defined

angular position. This page describes more general brushless motor principles,

though there is overlap.

Two key performance parameters of brushless DC motors are the Motor

constants Kv and Km (which are numerically equal in SI units). Here, Wye

configuration is designed because it gives high torque at low speed, but not as high

top speed as that of Delta configuration. The conveyor should be operated

depending on the time acquired by the pick and place to handle the component.

The receive signals from Inductive proximity sensor.

Fig 5.2 Torque-Speed characteristics

5.2.1 CONTROLLER IMPLEMENTATIONS

In our project, Brushless DC motor with the back EMF being sensed is used.

A typical controller contains 3 bi-directional outputs (i.e. frequency controlled

three phase output), which are controlled by a logic circuit. Simple controllers
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employ comparators to determine when the output phase should be advanced,

while more advanced controllers employ a microcontrollerto manage acceleration,

control speed and fine-tune efficiency.

Fig 5.3 Labelling of BLDC Motor

Controllers that sense rotor position based on back-EMF have extra

challenges in initiating motion because no back-EMF is produced when the rotor is

stationary. This is usually accomplished by beginning rotation from an arbitrary

phase, and then skipping to the correct phase if it is found to be wrong. This can

cause the motor to run briefly backwards, adding even more complexity to the

startup sequence.
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Fig 5.4 Sinusoidal Back EMF

5.2.2 MOTOR CONTROL POWER SUPPLIES

Fig 5.5 Wye Configuration

Typical brushless motors are permanent magnet synchronous AC motors,

combined with sensor electronics (detecting rotor position) and an AC signal

generator (Inverter) driven by a DC supply. Typical brushless inverters use a

switched power supply pulse width modulation to generate an AC drive signal.

Various terms are used to refer to the inverters/electronic control systems,

including "Vector Drives", and "VVVF drives" (variable voltage variable

frequency).
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Fig 5.6 Block diagram of BLDC Motor

5.2.3 FORMULA

Winding Power = Kt*Kt/R Kv = 1000 rpm / Vrms Kt = oz-in / Amp Kt = Kb * 1.35 Ke = Vrms / 1000 rpm Kb = V / 1000 rpm Back EMF = V/KRPM

5.3 DC GEAR MOTOR

The DC Gear motor, consisting of a DC electric motor and a gearbox, is at

the heart of several electrical and electronic applications. It is an extension of a DC

Motor. A geared DC Motor has a gear assembly attached to the motor. The speed

of motor is counted in terms of rotations of the shaft per minute and is termed as

RPM .The gear assembly helps in increasing the torque and reducing the speed.

Using the correct combination of gears in a gear motor, its speed can be reduced to

any desirable figure. This concept where gears reduce the speed of the vehicle but

increase its torque is known as gear reduction.


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Fig 5.7 DC Gear Motor

Here the High torque DC Gear Motor is used to drive the Auto Orientation

fixture. The drive is controlled by the signals received from the LDR. The LDRfunctioning is dependent on the light rays falling over those sensors from the

Halogen light source through the two reference holes.

Fig 5.8 Dimensions of DC Gear Motor

5.3.1 GEAR BLOCK

The RPM of the DC gear motor is 300 RPM. Thus enough torque that can be

obtained from it by which the complete setup can be moved. A set of planetary and

spur gears are used to get a gear ratio of 6:1. Therefore if the speed of the motor is

300 RPM then the output from the gear shaft is 50 RPM. This is a much more

manageable speed, and now the output torque has also been increased by

decreasing the speed.


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Power 3.6 W

Current 300 mA

Voltage 12v DC

Starting Current 300 mA

Torque 1.2Kgcm

Table 5.1 Rating of DC Motor

Fig 5.9 DC Gear Motor Characteristics

5.3.2 FEATURES

300RPM 12V DC motors with Metal Gearbox and Metal Gears 18000 RPM base motor 6mm Dia shaft with M3 thread hole Gearbox diameter 37 mm.


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Motor Diameter 28.5 mm Length 63 mm without shaft Shaft length 15mm 180gm weight 30kgcm torque No-load current = 800 mA, Load current = upto 7.5 A(Max) Recommended to be used with DC Motor Driver 20A orDual DC Motor

Driver 20A

Miniature gear motor work smoothly and efficiently, supporting theseelectrical and electronic applications.

DC geared motors reduce the complexity and cost of designing andconstructing for driving Auto Orientation fixture.

5.4 DC SERVO MOTOR

A servomotor is a rotary actuatorthat allows for precise control of angular

position. It consists of a motor coupled to a sensor for position feedback, through a

reduction gearbox. It also requires a relatively sophisticated controller, often a

dedicated module designed specifically for use with servomotors. In our project,

the DC servo motor actuates the Pick and Place that holds the vacuum gripper.

5.4.1 MECHANISM

As the name suggests, a servomotor is a servomechanism. More specifically,

it is a closed-loop servomechanism that uses position feedback to control its

motion and final position. The input to its control is a digital signal, representing

the position commanded for the output shaft.
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Fig 5.10 DC Servo Motor

The motor is paired with encoderto provide position and speed feedback.

The measured position of the output is compared to the command position, the

external input to the controller. If the output position differs from that required,

an error signal is generated which then causes the motor to rotate in either

direction, as needed to bring the output shaft to the appropriate position. As the

positions approach, the error signal reduces to zero and the motor stops.

The position-only sensing is done via a potentiometerand bang-bang

control of their motor; the motor always rotates at full speed (or is stopped). They

form the basis of the simple and cheap servos used forradio-controlled models. If

necessary both Speed and Position is sensed. Both of these enhancements, usually

in combination with a PID control algorithm, allow the servomotor to be brought

to its commanded position more quickly and more precisely, with

less overshooting.
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Fig 5.11 Characteristics of DC Servo Motor

5.4.2 ENCODERS

It would be possible to electrically differentiate their position signal to

obtain a speed signal, PID controllers that can make use of such a speed signal

generally warrant a more precise encoder.

The servomotors use optical encoders, eitherabsolute orincremental.

Absolute encoders can determine their position at power-on, but are more

complicated and expensive. Incremental encoders are simpler, cheaper and work at

faster speeds. Incremental systems, like stepper motors, often combine their

inherent ability to measure intervals of rotation with a simple zero-position sensor

to set their position at start-up.
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Fig 5.12 Dimensions of DC Servo Motor

The servomotors are rotary, but are used for ultimate control of a linear

motion. In some of these cases, a linear encoder is used. These servomotors avoid

inaccuracies in the drive train between the motor and linear carriage, but their

design is made more complicated as they are no longer a pre-packaged factory-

made system. They are designed with a controller module.

5.4.3 SPECIFICATIONS

Table 5.2 Rating of DC Servo Motor


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5.5 LIMIT SWITCH

A limit switch is a switch operated by the motion of a machine part or

presence of an object. They are used for control of a machine, as safety interlocks,

or to count objects passing a point

Fig 5.13 Limit Switch

Standardized limit switches for industrial control components with a roller

plunger operated. Limit switches may be directly mechanically operated by the

motion of the operating lever. Rarely, a final operating device will be directly
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controlled by the contacts of an industrial limit switch, but more typically the limit

switch will be wired through a control relay, a motorcontactorcontrol circuit, or as

an input to a programmable logic controller.

5.5.1 LIMIT SWITCH OPERATION

In most cases, a limit switch begins operating when a moving machine or a

moving component of a machine makes contact with an actuator or operating lever

that activates the switch. The limit switch then regulates the electrical circuit that

controls the machine and its moving parts. These switches can be used as pilot

devices for magnetic starter control circuits, allowing them to start, stop, slow

down, or accelerate the functions of an electric motor. Limit switches are installed

into machinery as control instruments for standard operations or as emergency

devices to prevent machinery malfunction. The switches are made as momentary

contact models.

5.6 SOLENOID VALVE

A solenoid valve is an electromechanically operated valve. The valve is

controlled by an electric current through the solenoid. In the two-port valve the

flow is switched on or off.

Fig 5.14 Solenoid Valve
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Multiple solenoid valves can be placed together on a manifold. Solenoid

valves are the most frequently used control elements in fluidics. Solenoids offer

fast and safe switching, high reliability, long service life, good medium

compatibility of the materials used, low control power and compact design.

5.6.1 OPERATION

A solenoid valve has two main parts: the solenoid and the valve. The

solenoid converts electrical energy into mechanical energy which, in turn, opens or

closes the valve mechanically. A direct acting valve has only a small flow circuit,

shown within section E of the diagram (this section is mentioned below as a pilot

valve). In this example, a diaphragm piloted valve multiplies this small pilot flow,

by using it to control the flow through a much larger orifice. Solenoid valves may

use metal seals or rubber seals, and may also have electrical interfaces to allow for

easy control. A spring may be used to hold the valve opened (normally open) or

closed (normally closed) while the valve is not activated.

Fig 5.15 Operation of Solenoid Valve
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A- Input side

B- Diaphragm

C- Pressure chamber

D- Pressure relief passage

E- Solenoid

F- Output side

The diagram to the right shows the design of a basic valve, controlling the

flow of air in this example. At the top figure is the valve in its closed state. The air

under pressure enters at A. B is an elastic diaphragm and above it is a weak spring

pushing it down. The function of this spring is irrelevant for now as the valve

would stay closed even without it. The diaphragm has a pinhole through its centre

which allows a very small amount of air to flow through it. This air fills the

cavity C on the other side of the diaphragm so that pressure is equal on both sides

of the diaphragm; however the compressed spring supplies a net downward force.

The spring is weak and is only able to close the inlet because air pressure is

equalized on both sides of the diaphragm.

In the previous configuration the small passage D was blocked by a pin

which is the armature of the solenoid E and which is pushed down by a spring. If

the solenoid is activated by drawing the pin upwards via magnetic force from the

solenoid current, the air in chamberC will flow through this passage D to the

output side of the valve. The pressure in chamberC will drop and the incoming

pressure will lift the diaphragm thus opening the main valve. Air now flows

directly from A to F.

When the solenoid is again deactivated and the passage D is closed again,

the spring needs very little force to push the diaphragm down again and the main
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valve closes. In practice there is often no separate spring, the elastomer diaphragm

is molded so that it functions as its own spring, preferring to be in the closed shape.

From this explanation it can be seen that this type of valve relies on a differential

of pressure between input and output as the pressure at the input must always be

greater than the pressure at the output for it to work. Should the pressure at the

output, for any reason, rise above that of the input then the valve would open

regardless of the state of the solenoid and pilot valve.

In some solenoid valves the solenoid acts directly on the main valve. Others use a

small, complete solenoid valve, known as a pilot, to actuate a larger valve. While

the second type is actually a solenoid valve combined with a pneumatically

actuated valve, they are sold and packaged as a single unit referred to as a solenoid

valve. Piloted valves require much less power to control, but they are noticeably

slower. Piloted solenoids usually need full power at all times to open and stay

open, where a direct acting solenoid may only need full power for a short period of

time to open it, and only low power to hold it.

5.7 SINGLE ACTING CYLINDER

A single-acting cylinder is a cylinderin which the working fluid acts on one

side of the piston only. A single-acting cylinder relies on the load, other cylinders,

or spring, to push the piston back in the other direction. Single-acting cylinders are

found in most kinds of reciprocating engine.
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Fig 5.16 Single CylinderActing

They are found to be the simple operated, cheapest and less fluid required

for operation. When the solenoid is operated and air pushes the cylinder forward, it

stays in that position until the air is inside it. When the air flow is stopped, the

cylinder retracts due to spring action.


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CHAPTER 6

SENSORS

6.1 INTRODUCTION

A sensor (also called detector) is a converterthat measures a physical

quantity and converts it into a signal which can be read by an observer or by an

(today mostly electronic) instrument. A sensor is a device which receives and

responds to a signal when touched. A sensor's sensitivity indicates how much the

sensor's output changes when the measured quantity changes. Sensors that measure

very small changes must have very high sensitivities. Sensors need to be designed

to have a small effect on what is measured; making the sensor smaller often

improves this and may introduce other advantages.

6.2 INDUCTIVE PROXIMITY SENSOR

An inductive sensor is an electronic proximity sensor, which detects metallic

objects without touching them.

Fig 6.1 Inductive Proximity Sensor

The sensorconsists of an induction loop. Electric current generates

a magnetic field, which collapses generating a current that falls asymptotically
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toward zero from its initial level when the input electricity ceases.

The inductance of the loop changes according to the material inside it and since

metals are much more effective inductors than other materials the presence of

metal increases the current flowing through the loop. This change can be detected

by sensing circuitry, which can signal to some other device whenever metal is

detected. Because the sensor does not require physical contact it is particularly

useful for applications where access presents challenges or where dirt is prevalent.

6.2.1 INDUCTION LOOP

An induction loop is an electromagnetic communication or detection system

which uses a moving magnet to induce an electrical current in a nearby wire.

Induction loops are used for transmission and reception of communication signals,

or for detection of metal objects in metal detectors or vehicle presence indicators.

Fig 6.2 Wiring Diagrams

6.2.2 INDUCTANCE

Inductance is the property of a conductor by which a change in current in the

conductor "induces" (creates) a voltage (electromotive force) in both the conductor

itself (self-inductance) and any nearby conductors (mutual inductance). This effect

derives from two fundamental observations of physics: First, that a steady current

creates a steady magnetic field (Oersted's law) and second, that a time-varying
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magnetic field induces a voltage in a nearby conductor (Faraday's law of

induction).

Fig 6.3 Dimensions of Inductive Proximity Sensor

From Lenz's law, in an electric circuit, a changing electric current through a

circuit that has inductance induces a proportional voltage which opposes the

change in current (self inductance). The varying field in this circuit may also

induce an e.m.f. in a neighbouring circuit (mutual inductance).

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Table 6.1 Inductive Proximity Sensor Specifications

6.3 OPTICAL PROXIMITY SENSORS

Optical proximity sensors generally cost more than inductive proximity

sensors, and about the same as capacitive sensors. They are widely used in

automated systems because they have been available longer and because some can

fit into small locations. These sensors are more commonly known as light beam

sensors of the thru-beam type or of the retro reflective type. Both sensor types are

shown below.


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Fig 6.4 Optical Proximity Sensor

6.3.1 CONSTRUCTION AND WORKING

A complete optical proximity sensor includes a light source, and a sensor

that detects the light. The light source is supplied because it is usually critical that

the light be "tailored" for the light sensor system. The light source generates light

of a frequency that the light sensor is best able to detect, and that is not likely to be

generated by other nearby sources. Infra-red light is used in most optical sensors.

To make the light sensing system more foolproof, most optical proximity sensor

light sources pulse the infra-red light on and off at a fixed frequency. The light

sensor circuit is designed so that light that is not pulsing at this frequency is

rejected.


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Fig 6.5 Light Intensity detected as a function of (a) Orientation, (b) Distance

The light sensor in the optical proximity sensor is typically a semiconductor

device such as a photodiode, which generates a small current when light energy

strikes it, or more commonly a phototransistor or a photo-darlington that allows

current to flow if light strikes it. Early light sensors used photoconductive materials

that became better conductors, and thus allowed current to pass, when light energy

struck them. Sensor control circuitry is also required. The control circuitry may

have to match the pulsing frequency of the transmitter with the light sensor.

Control circuitry is also often used to switch the output circuit at a certain light

level. Light beam sensors that output voltage or current proportional to the

received light level are also available.

Through beam type sensors are usually used to signal the presence of

an object that blocks light. If they have adjustable switching levels, they can be

used, for example, to detect whether or not bottles are filled by the amount of light


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that passes through the bottle. Retroflective type light sensors have the transmitter

and receiver in the same package. They detect targets that reflect light back to the

sensor. Retroreflective sensors that are focused to recognize targets within only a

limited distance range are also available.

Fig 6.6 Working of Optical Proximity Sensor


Model - FU-10

Detection typeDiffuse reflective Head shapeThreaded Head sizeM6 ViewEnd LensBuilt-in lens


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Smallest object detectable0.3 Detecting distance Mega10 to 30 mm Fine10 to 30 mm

Fibre type - Standard Fibre details2 m free out CommentBeam spot can be adjusted to target size. (Approx. 5g)

6.4 LIGHT DEPENDANT RESISTOR

A light dependent resistor (LDR) or a Photoresistor is a resistor in

which the resistance decreases with increasing incident light intensity; in other

words, it exhibits photoconductivity.

Fig 6.7 Light Dependant Resistor

A photoresistor is made of a high resistance semiconductor. If light falling

on the device is of high enough frequency, photons absorbed by the semiconductor

give bound electrons enough energy to jump into the conduction band. The

resulting free electron (and its holepartner) conduct electricity, thereby

lowering resistance. A photoelectric device can be either intrinsic or extrinsic.
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Fig 6.8 Symbol of LDR

An intrinsic semiconductor has its own charge carriers and is not an efficient

semiconductor, for example, silicon. In intrinsic devices the only available

electrons are in the valence band, and hence the photon must have enough energy

to excite the electron across the entire bandgap. Extrinsic devices have impurities,

also called dopants, added whose ground state energy is closer to the conduction

band; since the electrons do not have as far to jump, lower energy photons (that is,

longer wavelengths and lower frequencies) are sufficient to trigger the device.

Fig 6.9 Resistance as Function Illumination
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Fig 6.10 Spectral Response

If a sample of silicon has some of its atoms replaced by phosphorus atoms

(impurities), there will be extra electrons available for conduction. This is an

example of an extrinsic semiconductor. Photoresistors are basically photocells.


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Fig 6.11 Dimensions of LDR

6.4.1 ABSOLUTE MAXIMUM RATINGS

Voltage AC or DC Peak100V Current5mA Operating Dissipation at 25C 50mW* Operating Temperature Range - -25C + 75C*Derate Linearity from 50mW at 25C to 0W at 75C

6.4.2 ELECTRICAL CHARACTERISTICS


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LDRs or Light Dependent Resistors are very useful especially in light/dark

sensor circuits.

Table 6.2 Electrical Characteristics of LDR

Normally the resistance of an LDR is very high, sometimes as high as 1000

000 ohms, but when they are illuminated with light resistance drops dramatically.


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CHAPTER 7

PROGRAMABLE LOGIC CONTROLLER

7.1 INTRODUCTION

A Programmable Logic Controller, PLC or Programmable Controller is

a digital computerused forautomation ofelectromechanicalprocesses, such as

control of machinery on factory assembly lines, amusement rides, orlight fixtures.

The abbreviation "PLC" and the term "Programmable Logic Controller" are

registered trademarks of the Allen-Bradley Company (Rockwell Automation).

Fig 7.1 Programmable Logic Controller

PLCs are used in many industries and machines. Unlike general-purpose

computers, the PLC is designed for multiple inputs and output arrangements,

extended temperature ranges, immunity to electrical noise, and resistance to
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vibration and impact. Programs to control machine operation are typically stored in

battery-backed-up ornon-volatile memory.

Table 7.1 Functions of various terminals

A PLC is an example of a hard real time system since output results must be

produced in response to input conditions within a limited time, otherwise un

intended operation will result.

7.2 FUNCTIONALITY

The functionality of the PLC has evolved over the years to include

sequential relay control, motion control, process control, distributed control

systems and networking. The data handling, storage, processing power and

communication capabilities of some modern PLCs are approximately equivalent

to desktop computers.
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Fig 7.2 PLC Functions

PLC-like programming combined with remote I/O hardware, allow a

general-purpose desktop computer to overlap some PLCs in certain applications.

Regarding the practicality of these desktop computer based logic controllers, it is

important to note that they have not been generally accepted in heavy industry

because the desktop computers run on less stable operating systems than do PLCs,

and because the desktop computer hardware is typically not designed to the same

levels of tolerance to temperature, humidity, vibration, and longevity as the

processors used in PLCs. In addition to the hardware limitations of desktop based

logic, operating systems such as Windows do not lend themselves to deterministic

logic execution, with the result that the logic may not always respond to changes in

logic state or input status with the extreme consistency in timing as is expected

from PLCs. Still, such desktop logic applications find use in less critical situations,

such as laboratory automation and use in small facilities where the application is

less demanding and critical, because they are generally much less expensive than

PLCs.


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7.3 FEATURES OF PLC

The control actions of the entire system are done by KEYENCE - KV Series

PLC.

The salient features of Preferred PLC as follows

Ultra smaller in size High speed scan time Built - in access window Installation flexibility with expansion units User friendly Operator interface panel AC power built-in type Program write in RUN mode Improved debug environment

7.3.1 COMMON I/O SPECIFICATIONS

INPUT SPECIFICATION

Table 7.2 Input specification of PLC


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Fig 7.3 Frequency response chart

OUTPUT SPECIFICATION

Table 7.3 Output specification of PLC

7.3.2 SCAN TIME

A PLC program is generally executed repeatedly as long as the controlled

system is running. The status of physical input points is copied to an area of

memory accessible to the processor, sometimes called the "I/O Image Table".


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The minimum scan time is 140 s and minimum instruction execution time

is 0.7s, which is the fastest control than other PLCs. The program is then run

from its first instruction rung down to the last rung

It takes some time for the processor of the PLC to evaluate all the rungs and

update the I/O image table with the status of outputs. This scan time may be a few

milliseconds for a small program or on a fast processor, but older PLCs running

very large programs could take much longer (say, up to 100 ms) to execute the

program. If the scan time was too long, the response of the PLC to process

conditions would be too slow to be useful.

Fig 7.4 Scan time of PLC

As PLCs became more advanced, methods were developed to change the

sequence of ladder execution, and subroutines were implemented. This simplified

programming could be used to save scan time for high-speed processes; forexample, parts of the program used only for setting up the machine could be

segregated from those parts required to operate at higher speed.


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7.3.3 SYSTEM SCALE

A small PLC will have a fixed number of connections built in for inputs and

outputs. Typically, expansions are available if the base model has insufficient I/O.

KV series PLCs have a chassis (also called a rack) into which are placed modules

with different functions. The processor and selection of I/O modules are

customized for the particular application.

7.3.4 PERFORMANCE SPECIFICATION


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Table 7.4 Performance specification

Several racks can be administered by a single processor, and may have

thousands of inputs and outputs. A special high speed serial I/O link is used so that

racks can be distributed away from the processor, reducing the wiring costs for

large plants.


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7.3.5 USER INTERFACE

PLCs may need to interact with people for the purpose of configuration,

alarm reporting or everyday control. A human-machine interface (HMI) is

employed for this purpose. HMIs are also referred to as man-machine interfaces

(MMIs) and graphical user interface (GUIs). A simple system may use buttons and

lights to interact with the user. Text displays are available as well as graphical

touch screens. More complex systems use programming and monitoring software

installed on a computer, with the PLC connected via a communication interface.

Fig 7.5 PLC User Interface

7.3.6 COMMUNICATIONS

PLCs have built in communications ports, usually 9-pin RS-232, but

optionally EIA-485 orEthernet. Modbus, BACnet orDF1 is usually included as

one of the communications protocols. Other options include
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various fieldbuses such as DeviceNet orProfibus. Other communications protocols

that may be used are listed in the List of automation protocols.

Most modern PLCs can communicate over a network to some other system,

such as a computer running a SCADA (Supervisory Control and Data Acquisition)

system or web browser.

PLCs used in larger I/O systems may have peer-to-peer(P2P)

communication between processors. This allows separate parts of a complex

process to have individual control while allowing the subsystems to co-ordinate

over the communication link. These communication links are also often used

forHMI devices such as keypads orPC-type workstations.

7.3.7 PROGRAMMING

PLC programs are typically written in a special application on a personal

computer, and then downloaded by a direct-connection cable or over a network to

the PLC. The program is stored in the PLC either in battery-backed-up RAM or

some other non-volatile flash memory. Often, a single PLC can be programmed to

replace thousands ofrelays.

Under the IEC 61131-3 standard, PLCs can be programmed using standards-

based programming languages. A graphical programming notation

called Sequential Function Charts is available on certain programmable controllers.
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Fig 7.6 AND, OR, NOT in PLC Programming

Initially most PLCs utilized Ladder Logic Diagram Programming, a modelwhich emulated electromechanical control panel devices (such as the contact and

coils of relays) which PLCs replaced. This model remains common today.

IEC 61131-3 currently defines five programming languages for

programmable control systems: function block diagram (FBD), ladder

diagram (LD), structured text (ST; similar to the Pascal programming

language), instruction list (IL; similar to assembly language) and sequentialfunction chart (SFC). These techniques emphasize logical organization of

operations.
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Fig 7.7 Ladder Logic Programming in PLC

While the fundamental concepts of PLC programming are common to all

manufacturers, differences in I/O addressing, memory organization and instruction

sets mean that PLC programs are never perfectly interchangeable between differentmakers. Even within the same product line of a single manufacturer, different

models may not be directly compatible.

7.3.8 DISCRETE AND ANALOGUE SIGNALS

Discrete signals behave as binary switches, yielding simply an ON or OFF

signal (1 or 0, True or False, respectively). Push buttons, Limit switches,

and photoelectric sensors are examples of devices providing a discrete signal.

Discrete signals are sent using either voltage orcurrent, where a specific range is

designated as ON and another as OFF. For example, a PLC might use 24 V DC

I/O, with values above 22 V DC representing ON, values below 2VDC
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representing OFF, and intermediate values undefined. Initially, PLCs had only

discrete I/O.

Fig 7.8 Discrete and Analogue Signal

Analogue signals are like volume controls, with a range of values between

zero and full-scale. These are typically interpreted as integer values (counts) by the

PLC, with various ranges of accuracy depending on the device and the number of

bits available to store the data. As PLCs typically use 16-bit signed binary

processors, the integer values are limited between -32,768 and +32,767. Pressure,

temperature, flow, and weight are often represented by analogue signals. Analogue

signals can use voltage orcurrent with a magnitude proportional to the value of the

process signal. For example, an analogue 0 - 10 V input or4-20 mA would

be converted into an integer value of 0 - 32767. Current inputs are less sensitive to

electrical noise (i.e. from welders or electric motor starts) than voltage inputs.
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CHAPTER VIII

SOFTWARE

8.1 INTRODUCTION

The Ladder Builder is software which allows creating sequence of programs.

It offers excellent functionality and advanced programming processing ability. The

Ladder logic is widely used to program PLCs, where sequential control of a

process or manufacturing operation is required.Ladder logic can be thought of as arule-based language rather than a procedural language. A "rung" in the ladder

represents a rule. When implemented with relays and other electromechanical

devices, the various rules "execute" simultaneously and immediately. When

implemented in a programmable logic controller, the rules are typically executed

sequentially by software, in a continuous loop (scan).

In this project KV Ladder builder is the software used to implement the

process control logics in PLC.

8.2 OVERVIEW OF SOFTWARE

The KV Builder can simulate program execution even without a PLC

connected. Providing a single step execution (forward and reverse) in addition to a

regular scan execution function increases debugging efficiency.

The following functions are provided in the Ladder Builder

Editor function Simulator function Monitor function


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8.2.1 EDITOR FUNCTION

The function which creates the ladder diagram using diversified instruction

words of the ladder language, Registers comments to contacts. Comments can be

transferred to PLC. Which Converts the ladder diagram into machine code and

displays the ladder diagram, mnemonic list, label comment and device use status

list, etc., on the screen

Fig 8.1 Editor Window

8.2.2 SIMULATOR FUNCTION

It simulates the operation of the ladder diagram even if the PLC is not

connected, and allows debugging of the program.


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Fig 8.2 Simulator Window

Which provides a continuous scan execution mode, one scan execution mode, one

step execution mode, etc. so that errors be confidently located and also enables

execution of a step in the reverse direction once or continuously.

8.2.3 MONITOR FUNCTION

This window monitors the contact ON/OFF status on a real-time, on-line

basis using the ladder diagram created.


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Fig 8.3 Monitor Window

Simultaneously displays the timing chart, and transfers programs to PLC.

8.3 LADDER DIAGRAM

Ladder logic has contacts that make or break circuits to control coils each

coil or contact corresponds to the status of a single bit in the programmable

controller's memory. The coil (output of a rung) may represent a physical output

which operates some device connected to the programmable controller, or may

represent an internal storage bit for use elsewhere in the program.


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Fig 8.4 Relay ladder logicAuto operation

Fig 8.5 Relay ladder logicManual operation

Fig 8.6 Relay ladder logicEmergency Stop


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8.3.1 I/O DESCRIPTIONS

S. No Address Description

1 0000 Main power ON/OFF

2 0001 INDUCTIVE PROXIMITY SENSOR-1

3 0002 SERVO MOTOR ON

4 0003 OPTICAL PROXIMITY SENSOR

5 0004 LIMIT SWITCH

6 0005 REED SWITCH

7 0006 INDUCTIVE PROXIMITY SENSOR-2

8 0007 LIGHT DEPENDANT RESISTOR

9 0008 EMERGENCY STOP

Table 8.1 Input Descriptions

S. No Address Description

1 0500 CONVEYOR MOTOR ON/OFF

2 0501 SENSOR SIGNAL SET COIL

3 0502 SOLENOID VALVE EXCITATION

4 0503 VACUUM SOURCE ON/OFF

5 0504 SERVO MOTOR FORWARD/REVERSE

6 0505 DC MOTOR

Documents

Automatic horn housing conveying and positioning system