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Automatic Bottle Filling Plant

A PROJECT REPORT

Submitted bySANDEEP KUMAR(08-TIB-1168)

VIDIT PARASHAR (08-TIB-1290)

Submitted in the partial fulfillment of the requirements for the award of degree

Of

BACHELOR OF TECHNOLOGY

IN

ELECTRONICS & COMMUNICATION ENGINEERING

The Technological Institute of Textile and Sciences, Bhiwani

.

MAHARISHI DAYANAND UNIVERSITY, ROHTAK

(2008-2012)

Department of Electronics and Communication engineering

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CERTIFICATE OF APPROVAL

The foregoing project work report entitledAUTOMATIC BOTTLE FILLINGPLANT, is a hereby approved as a creditable work and has been presented in asatisfactory manner to warrant its acceptance as prerequisite to the degree for

which it has been submitted. It is understood that but this approval, the

undersigned do not necessarily endorse any conclusion drawn or opinion expressed

therein, but approve the project work for the purpose for which it is submitted.

Mrs. Priyanka Singh(Internal Examiner) (External Examiner)

Mr. Kamal Sardana(Head of the Department)

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CERTIFICATE

This is to certify that the work presented in the project report entitle

AUTOMATIC BOTTLE FILLING PLANT in the partial fulfillment of therequirement for the award of Degree of Bachelor of Technology in Electronics

and Communication engineering of The Technological Institute of Textile and

Sciences, Bhiwani is an authentic work carried out under my supervision and

guidance. To the best of my knowledge ,the content of this project work not form a

basis for the award of any previous Degree to anyone else.

Date:

Mrs. Priyanka Singh Mr. S.K Jha.(Project Guide) (Project Coordinator)

Mr. Kamal Sardana( Head of the Department)

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Acknowledgement

Knowledge is an experience gained in life. It is the choicest possession, which should not be

shelved but should be happily shared with others. In this regard I am extremely fortunate in

having Mrs.Priyanka Singh, Lect.., ECE dept. as my project guide .It was he ,who provided

proper direction in the completion of this project work.

I have often been guilty of encroaching upon the privacy of this home but not even once I was

disappointed .His willingness to share his experience and spontaneous suggestion on any

problem encourage me tremendously to achieve my goal .I am sure his directive will show me

the light in future also.

I am very much thankful to Sh. Kamal Sardana ,HOD ,and ECE dept. for his encouragement,

valuable suggestion and moral support provided by him.

At the juncture,I feel at the deepest of my heart to acknowledge the encouragement and blessing

of my mother and sister.

Last but not the least ,words can hardly express my heartfelt gratitude towards my project

coordinator Mr. S.K Jha,who stood by me and helped in every way possible during the

completion of this project.

Abhinav (08-Ec-018/14)

Ankit (08-Ec-003/29)

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Abstract

The bottle filling system is an automated System. Here the objective is to fill bottle in a sequenceand at a random process. For this reason plc has been implemented. Here when the empty bottle

is placed on the rotating conveyor belt, the bottle starts moving with Belt. As soon as the bottle

comes in front of position Sensor, a signal goes to plc, resulting stop to the motor & after some

delay implied by programming, solenoid Valve opens and filling starts. After some delay,

Solenoid valve stops causing stop to fill the bottle & a fter few more seconds conveyor starts.

This process Continues in a loop & filling purpose is accomplished

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TABLE OF CONTENTS

TITLE PAGE NO.

1. INTRODCTION .1

1.1 AUTOMATION .. 21.2 DIFFERENT COMPONENTS USED IN AUTOMATION .

1.3 DIFFERENT CONTROL SYSTEMS USED IN AUTOMATION .

1.4 AUTOMATION IN BOTTLE FILLING PLANT .

1.5 LAYOUT ..

2. COMPONENTS LIST.3

2.1 CONVEYOR ..

2.1 PLC.

2.1 MOTORS.... 3

2.2 SENSORS 3

2.3 SMPS 3

2.4 RELAYS

2.4 NO & NC SWITCH.

2.5 INDICATORS.

3. CONVEYOR .

3.1 DESIGN ..

3.2 INDUTRIES THAT USES CONVEYOR

3.4 TYPES OF CONVEYOR

3. PLC.. 11

3.1 INTRODUCTION TO PLC.

3.2 FEATURES OF PLC

3.3 GENERATION OF INPUT SIGNAL

3.4 GENERATION OF OUTPUT SIGNAL

3.5 PROGRAMMING

3.6 LADDER LOGIC

3.7 EXAMPLE OF LADDER LOGIC PROGRAM .

3.8 INSTRUCTIONS AND SYMBOLS

3.9 PROGRAMMING FOR START/STOP OF MOTOR

4. MOTORS.

4.1 INTRODUCTION. 4.2 PRINCIPLE OF OPERATION .

4.3 DC SERIES MOTORS

4.4 CONSTRUCTION .

4.5 CHARECTRISTICS

4.6 APPLICATIONS .

5. SENSORS

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5.1 USE .

5.2 OPERATING PRINCIPLE FOR PHOTOELECTRIC SENSORS

5.3 CHARECTRISTICS CURVES ..

6. RELAYS

6.1 BASIC DESIGN AND OPERATION

6.2 24V DC 8 PIN BASE RELAY ..

7. SMPS ..

7.1 OPERATION

7.2 24V AC/DC SMPS .

8. SWITCHES.

8.1 SWITCH IN CIRCUIT THEORY ....

8.2 CONTACTS .

8.3 NO PUSH BUTTONS ..

8.4 NC PUSH BUTTONS ..

3.6.2 INDICATORS .12. PRECAUTIONS..........50

13. REFERENCE5

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LIST OF FIGURES

FIGURE TITLE PAGE

NO. NO.

1 IAYOUT 92 CONVEYOR DESIGN 113 ALLEN BRADELY PLC 134 DIAGRAM SHOWING ENERGIZED INPUT 145 DIAGRAM SHOWING ENERGIZED OUTPUT 156 UNIVERSAL MOTOR CONSTRUCTION 207 24V DC SERIES MOTOR 248 BASIC DIAGRAM OF PHOTOELECTRIC SENSOR 279 DC PHOTOELECTRIC SENSOR 2810 WIRING OF DC PHOTOELECTRIC SENSOR 2911 FORK SHAPE DC PHOTOELECTRIC SENSOR 3012 WIRING OF FORK SHAPE SENSOR 3013 AC PHOTOELECTRIC SENSOR 3114 WIRING OF AC PHOTOELECTRIC SENSOR 3215 CHARECTRISTICS CURVES OF PHOTOELECTRIC SENSOR 3216 8 PIN RELAY 3417 8 PIN RELAY BASE 3418 24V AC/DC SMPS 3519 NO PUSH BUTTONS 3720 NC PUSH BUTTONS 3721 INDICATORS 38

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INTRODUCTIONControlling is necessary in every process. It can be done either manually or with the help of

some devices. In manual control, an operator keeps track on whole process and adjusts the

controls. But nowadays it is not possible at industrial levels or large scale productions. Because ahuman being can not measure the minute changes that can results in big problems. Manualcontrol may be used in non- critical applications where major upsets are unlikely to occur, where

any process conditions occur slowly & in small increments and where a minimum of operator

attention is required. But for critical operations some control systems has to be used forautomation.

1. Automation: -

Making products under the control of computers and programmable controllers is known as

industrial automation. Manufacturing assembly lines as well as stand-alone machine tools (CNC

machines) and robotic devices fall into this category. Automation is delegation of human controlfunctions to technical equipment for increasing productivity, better quality, increasing safety in

working conditions reducing manpower & cost.

2. Different Components Used in Automation: -

The components of automation system include- Sensors for sensing the input parameters- Transmitters for transmitting the raw signal in electrical form- Control system which includes PLC, DCS & PID controllers- Output devices like drives, control valves, solenoid valves, coils etc.

3. Different Control Systems Used in Automation: -

- PID controller based control system- PLC based control system- DCS based control system- PC based control system

4. Automation in Bottle Filling Plants: -

In an automatic bottle filling plant the main objective is to fill a large number of bottles

automatically. Here we have made a mini project of bottle filling plant. In this there is aconveyor belt folded on two shafts. Shafts are rotated with the help of motor by which belt also

rotates. The bottle is placed on the belt. On the conveyor there is a sensor. Where bottle reaches

in front of sensor the motor will stop. This controlling is done with the help of PLC. The PLC isprogrammed with a specified timing. The bottle will stop for that time after sensing of sensor.

During this time bottle will be field via tank. The flow of water is controlled with the help of

solenoid valve whose controlling is done by PLC. After the specified time the conveyor willmove again. At the corner of conveyor there is another sensor which will sense the position of

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bottle. When the second sensor`s output goes high, the lifting system will be energized. The lifter

will lift the bottle and will put the bottle on the platform made near to conveyor. During thislifting period another bottle is filling at the tank. In this manner the whole process goes until the

all bottles get filled. To start the conveyor an NO switch is used and to stop NC switch is used.

Two indicators are also used one green and another red. The green indicator glows when

conveyor moves and red will glow at the time of filling.

5. Layout: -

BOTTELING PLANT

FILLING TANK R-3 R-4

PULLEY

BOTTELES E.M. COIL

S-1 s-2

R-1 R-2 CONTAINER

M - 1

Fig 1 Layout

ABBRIVATION USED:--

R = ROLLER

S = SENSOR

M = MOTOR

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COMPONENT LIST

1. CONVEYOR

2. PLC

3. MOTORS OF 24V WITH HIGH TORQUE

4. TWO NPN PHOTOELECTRIC SENSORS OF 24V DC

5. ADAPTOR OF 24V DC

6.

TWO RELAYS 24V DC

7. ONE NO & ONE NC SWITCH

8. TWO INDICATORS ONE RED AND ONE GREEN

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CONVEYOR

A conveyor system is a common piece of mechanical handling equipment that moves

materials from one location to another. Conveyors are especially useful in applications

involving the transportation of heavy or bulky materials. Conveyor systems allow quick and

efficient transportation for a wide variety of materials, which make them very popular in thematerialhandling and packaging industries. Many kinds of conveying systems are available,

and are used according to the various needs of different industries. There are chain conveyors(floor and overhead) as well. Chain conveyors consist of enclosed tracks, I-Beam, towline,

power & free, and hand pushed trolleys.

1. Design: -

Here we have used conveyor for moving the bottles. We use wood to make the conveyor

base. The length of the base we made is 83 cm. At the end of the base we have attached twopulleys, on which belt is wounded. The pulleys are fixed in the bearings to reduce the

friction. To fix the pulleys four bearings are used. Of the two pulleys one is kept free andanother is made chain driven. The chain is connected to the motor which rotates the pulleys.A belt is wounded on the two pulleys which convey the bottles the pulleys are rotated with

chain. The sprockets are fixed on motor and pulley each. The whole system is placed on a

board. In the middle a sensor is connected which senses the presence of any object on theconveyor belt.

Fig 2 Conveyor design
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2. Industries That Use Conveyor Systems: -

Conveyor systems are used widespread across a range of industries due to the numerous benefits

they provide.

Conveyors are able to safely transport materials from one level to another, which whendone by human labor would be strenuous and expensive. They can be installed almostanywhere, and are much safer than using a forklift or other machine to move materials.

They can move loads of all shapes, sizes and weights. Also, many have advanced safetyfeatures that help prevent accidents.

There are a variety of options available for running conveying systems, including thehydraulic, mechanical and fully automated systems, which are equipped to fit individual

needs.

Conveyor systems are commonly used in many industries, including the automotive, agricultural,

computer, electronic, food processing, aerospace, pharmaceutical, chemical, bottling and

canning, print finishing and packaging. Although a wide variety of materials can be conveyed,some of the most common include food items such as beans and nuts, bottles and cans,

automotive components, scrap metal, pills and powders, wood and furniture and grain and

animal feed. Many factors are important in the accurate selection of a conveyor system. It isimportant to know how the conveyor system will be used beforehand. Some individual areas that

are helpful to consider are the required conveyor operations, such as transportation, accumulation

and sorting, the material sizes, weights and shapes and where the loading and pickup points needto be.

3. Types of conveyor systems: -

Gravity roller conveyor Gravity skate wheel conveyor Belt conveyor Wire mesh conveyors Plastic belt conveyors Bucket conveyors Flexible conveyors Vertical conveyors Spiral conveyors Vibrating conveyors Pneumatic conveyors Belt driven live roller conveyors Lineshaft roller conveyor Chain conveyor Screw conveyor Chain driven live roller conveyor Overhead conveyors Dust proof conveyors Pharmaceutical conveyors
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PLC

1. Introduction

A Programmable Logic Controller, PLC, or Programmable Controller is a digital computer

used for automation of industrial processes, such as control of machinery on factory assemblylines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output

arrangements, extended temperature ranges, immunity to electrical noise, and resistance to

vibration and impact. Programs to control machine operation are typically stored in battery-

backed or non-volatile memory. A PLC is an example of a real time system since output results

must be produced in response to input conditions within a bounded time, otherwise unintended

operation will result.

PLC and Programmable Logic Controller are registered trademarks of the Allen-Bradley

Company.

2. Features of PLCs

Fig 3 Allen Bradley PLC

Photograph showing several input and output modules of a single Allen-Bradley PLC.
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With each module having sixteen "points" of either input or output, this PLC has the ability to

monitor and control dozens of devices. Fit into a control cabinet, a PLC takes up little room,especially considering the equivalent space that would be needed by electromechanical relays to

perform the same functions:

The main difference from other computers is that PLC is armored for severe condition (dust,moisture, heat, cold, etc) and has the facility for extensive input/output (I/O) arrangements.

These connect the PLC to sensors and actuators. PLCs read limit switches, analog processvariables (such as temperature and pressure), and the positions of complex positioning systems.

Some even use machine vision. On the actuator side, PLCs operate electric motors, pneumatic or

hydraulic cylinders, magnetic relays or solenoids, or analog outputs. The input/output

arrangements may be built into a simple PLC, or the PLC may have external I/O modulesattached to a computer network that plugs into the PLC.

Many of the earliest PLCs expressed all decision making logic in simple ladder logic which

appeared similar to electrical schematic diagrams. The electricians were quite able to trace out

circuit problems with schematic diagrams using ladder logic. This program notation was chosento reduce training demands for the existing technicians. Other early PLCs used a form of

instruction list programming, based on a stack-based logic solver.

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.

3. Generation of Input Signal

Inside the PLC housing, connected between each input terminal and the Common terminal, is an

opto-isolator device (Light-Emitting Diode) that provides an electrically isolated "high" logic

signal to the computer's circuitry (a photo-transistor interprets the LED's light) when there is 120

VAC power applied between the respective input terminal and the Common terminal. Anindicating LED on the front panel of the PLC gives visual indication of an "energized" input

:

Fig 4 Diagram Showing Energized input terminal X1
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4. Generation of Output Signal

Output signals are generated by the PLC's computer circuitry activating a switching device

(transistor, TRIAC, or even an electromechanical relay), connecting the "Source" terminal to anyof the "Y-" labeled output terminals. The "Source" terminal, correspondingly, is usually

connected to the L1 side of the 120 VAC power source. As with each input, an indicating LEDon the front panel of the PLC gives visual indication of an "energized" output

In this way, the PLC is able to interface with real-world devices such as switches and solenoids.

The actual logic of the control system is established inside the PLC by means of a computerprogram. This program dictates which output gets energized under which input conditions.

Although the program itself appears to be a ladder logic diagram, with switch and relay symbols,

there are no actual switch contacts or relay coils operating inside the PLC to create the logical

relationships between input and output. These are imaginary contacts and coils, if you will. The

program is entered and viewed via a personal computer connected to the PLC's programmingport.

Fig 5

Diagram Showing Energized Output Y1

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5. Programming

Early PLCs, up to the mid-1980s, were programmed using proprietary programming panels or

special-purpose programming terminals, which often had dedicated function keys representingthe various logical elements of PLC programs. Programs were stored on cassette tape cartridges.

Facilities for printing and documentation were very minimal due to lack of memory capacity.More recently, PLC programs are typically written in a special application on a personalcomputer, and then downloaded by a direct-connection cable or over a network to the PLC. The

very oldest PLCs used non-volatile magnetic core memory but now the program is storedin thePLC either in battery-backed-up RAM or some other non-volatile flash memory.

Early PLCs were designed to be used by electricians who would learn PLC programming on thejob. These PLCs were programmed in "ladder logic", which strongly resembles a schematic

diagram of relay logic. Modern PLCs can be programmed in a variety of ways, from ladder logicto more traditional programming languages such as BASIC and C. Another method is State

Logic, a Very High Level Programming Language designed to program PLCs based on State

Transition Diagrams.

6. Ladder logicLadder logic is a method of drawing electrical logic schematics. It is now a graphical language

very popular for programming Programmable Logic Controllers (PLCs). It was originally

invented to describe logic made from relays. The name is based on the observation that programsin this language resemble ladders, with two vertical "rails" and a series of horizontal "rungs"

between them.

A program in ladder logic, also called a ladder diagram, is similar to a schematic for a set of

relay circuits. An argument that aided the initial adoption of ladder logic was that a wide varietyof engineers and technicians would be able to understand and use it without much additional

training, because of the resemblance to familiar hardware systems. (This argument has become

less relevant given that most ladder logic programmers have a software background in more

conventional programming languages, and in practice implementations of ladder logic havecharacteristicssuch as sequential execution and support for control flow features that make

the analogy to hardware somewhat imprecise.)

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

manufacturing operation is required. Ladder logic is useful for simple but critical controlsystems, or for reworking old hardwired relay circuits. As programmable logic controllers

became more sophisticated it has also been used in very complex automation systems.

Ladder logic can be thought of as a rule-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
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software, in a loop. By executing the loop fast enough, typically many times per second, the

effect of simultaneous and immediate execution is obtained. In this way it is similar to other rule-based languages, like spreadsheets or SQL. However, proper use of programmable controllers

requires understanding the limitations of the execution order of rungs.

7. Example of a simple ladder logic program

The language itself can be seen as a set of connections between logical checkers (relay contacts)

and actuators (coils). If a path can be traced between the left side of the rung and the output,

through asserted (true or "closed") contacts, the rung is true and the output coil storage bit is

asserted (1) or true. If no path can be traced, then the output is false (0) and the "coil" by analogyto electromechanical relays is considered "de-energized". The analogy between logical

propositions and relay contact status is due to Claude Shannon.

Ladder logic has "contacts" that "make" or "break" "circuits" to control "coils." Each coil orcontact corresponds to the status of a single bit in the programmable controller's memory. Unlike

electromechanical relays, a ladder program can refer any number of times to the status of a singlebit, equivalent to a relay with an indefinitely large number of contacts.

So-called "contacts" may refer to inputs to the programmable controller from physical devicessuch as pushbuttons and limit switches, or may represent the status of internal storage bits which

may be generated elsewhere in the program.

Each rung of ladder language typically has one coil at the far right. Some manufacturers may

allow more than one output coil on a rung.

-- ( ) -- a regular coil, true when its rung is true

-- (\) -- a "not" coil, false when its rung is true

-- [ ] -- A regular contact, true when its coil is true (normally false)

-- [\] -- A "not" contact, false when its coil is true (normally true)

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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8. Generally Used Instructions & symbol for PLC Programming

Input Instruction--[ ]-- This Instruction is Called IXC or Examine If Closed.

i.e.; if a NO switch is actuated then only this instruction will be true. If a NC switch isactuated then this instruction will not be true and hence output will not be generated.

--[\]-- This Instruction is Called IXO or Examine If Open

i.e.; If a NC switch is actuated then only this instruction will be true. If a NC switch isactuated then this instruction will not be true and hence output will not be generated.

Output Instruction--( )-- This Instruction Shows the States of Output.

i.e.; if any instruction either XIO or XIC is true then output

will be high. Due to high output a 24 volt signal is generated from

PLC processor.

Rung: -

Rung is a simple line on which instruction are placed and logics are created

E.g.;---------------------------------------------

Here is an example of what one rung in a ladder logic program might look like. In real life, theremay be hundreds or thousands of rungs.

For example

1. ----[ ]---------|--[ ]--|------( )--

X | Y | S

| ||--[ ]--|

Z

The above realizes the function: S = X AND (Y OR Z)

Typically, complex ladder logic is 'read' left to right and top to bottom. As each of the lines (or

rungs) is evaluated the output coil of a rung may feed into the next stage of the ladder as an

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input. In a complex system there will be many "rungs" on a ladder, which are numbered in order

of evaluation.

1. ---- [ ] -----------|--- [ ] ---|---- ( )--

X | Y | S

| ||---[ ]---|

Z

2. ---- [ ] ---- [ ] ------------------- ( )--

S X T

2. T = S AND X where S is equivalent to #1 above

This represents a slightly more complex system for rung 2. After the first line has beenevaluated, the output coil (S) is fed into rung 2, which is then evaluated and the output coil T

could be fed into an output device (buzzer, light etc...) or into rung 3 on the ladder. (Note that the

contact X on the 2nd rung serves no useful purpose, as X is already a 'AND' function of S fromthe 1st rung.)

This system allows very complex logic designs to be broken down and evaluated.

9. Programming for Start/Stop of Motor by PLC: -

Often we have a little green "start" button to turn on a motor, and we want to turn it off with a

big red "Stop" button.

--+----[ ]--+----[\]----( )---| start | stop run| |

+----[ ]--+

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MOTORS

1. Introduction: -

The universal motor is characterized by its ability to operate, with substantially the same

performance, on direct as well as alternating current of frequencies up to 60 Hz. It develops more

horsepower per kg than other ac motors, principally because of its high speed. These motors are

series-wound and have series characteristics on both alternating and direct current, except when

governors or other means are used to control their speed. No-load speeds are high, sometimes

well over 20,000 rpm; but the armatures are designed so that they will not be damaged at these

speeds. Power ratings vary from 10 mhp to 1 hp, for continuous-rated motors, and even higher

for intermittent-rated motors. They are usually designed for full-load operating speeds of 4000 to

16,000 rpm in the larger horsepower ratings, and up to 20,000 or more in the smaller power

ratings. At the higher speeds, better universal characteristics (i.e., more nearly the same

performance characteristics on both alternating and direct current) can be obtained, as well as

more output per kg.

Universal Motor Construction

Fig 6

Universal motors can operate on either AC or DC power. The rotor has coils that are connected

to an external circuit through a commutator on the shaft, as shown in the schematic. Note that the

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field in the rotor will oppose the field in the stator at any given moment, regardless of whether or

not the polarity of the supply current changes with time. This feature gives the universal motor

its unique characteristic. The price of versatility is efficiency; universal motors are not as

efficient as similarly-constructed AC and DC series motors.

2. Principle of operation: -

Operation on AC: -

If alternating current is applied to a series motor, it will start and run. The current in the arma-

ture circuit, of course, reverses 100 times per second (for 50 Hz), but the field excitation and

stator flux likewise reverse 100 times per second, and these reversals take place in time phasewith the armature current. On alternating current, the torque varies instantaneously 100 times

per second, but the torque developed is always in one direction. (It is, perhaps, superfluous to

say that the motor operates in the same direction of rotation on alternating current that it does

on direct current.) However, there are some effects present on AC operation that are not present

on DC operation.

(1) Laminated-field construction: Because the stator flux alternates, it is necessary to use a

laminated-field structure in order to reduce hysteresis and eddy-current losses.

(2) Reactance voltage: In a simple dc circuit, the current is limited by the resistance. In a

simple ac circuit, the current is limited by the impedance and not solely by the ohmic

resistance. The impedance is made up of two components, resistance and reactance. Reactance

is present in an ac circuit whenever a magnetic circuit is set up by the current flowing in the

electric circuit. Reactance is, therefore, present to a marked degree in the case of a universal

motor. This reactance voltage, which is present during ac but not dc operation, absorbs some of

the line voltage, reducing the voltage applied to the armature, so that the speed of the motor,

for any given current, tends to be lower on alternating than on direct current. In other words,

the effective voltage on the armature for any given current is less on ac than on dc operation.

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(3) Saturation effect: In the Universal motor it is observed that the tendency of the

reactance voltage is to make the speed lower on alternating than on direct current. There is

another effect, which gives the opposite tendency. This effect is simply that a given root-mean

square (rms) value of alternating current will produce less rms alternating flux than will a

direct current of the same value because of saturation effects in the iron. At low currents and

high speeds, the reactance voltage is relative1y unimportant, and this saturation effect usually

causes the motor to operate at a higher no-load speed on alternating than on direct current.

Likewise, under 25-Hz operation, the saturation effect is as pronounced as on 50 Hz, but the

effect of the reactance voltage is appreciably less, in the ratio of 25:50. The net result is that the

motor may sometimes operate at a higher speed on 25 Hz than it does on direct current.

(4) Commutation and brush life. The commutation on alternating current is substantiallypoorer than on direct current, and the brush life is likewise less. The principal reason for the

poorer commutation on alternating current is because of the voltage induced in the short-

circuited coils undergoing commutation by the transformer action of the alternating main field.

No such transformer voltage exists when the motor is operated on direct current.

Operation on Direct Current: -

(1) How torque is developed. A simple dc motor is represented schematically. Armature

windings, together with commutator and brushes, are so arranged that the flow of current is in

one direction in all the conductors on one side of the armature, and in the opposite direction in all

the conductors on the opposite side of the armature. This condition is represented in the figure by

the use of dots to indicate current flowing toward the observer, and by plus signs (representing

the tail of an arrow) to indicate current flowing away from the observer, perpendicularly to the

plane of the paper. The field winding sets up a magnetic field as shown in the figure. It is a

simple fundamental law of motor action that, if current is passed through a conductor which isperpendicular to a magnetic field, a mechanical force will be exerted on the conductor, mutually

perpendicular to both the conductor and the direction of the field. A rule for the direction of this

force is given in the left-hand rule." Application of this rule to gives an upward force on all

conductors to the left, and a downward force on all conductors to the right, so that a torque is

developed in a clockwise direction.

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(2) Counter emf: An understanding of the nature and role of counter electromotive force

(emf) is absolutely essential to any comprehension of the way any type of dc motor works. Again

let us refer to circuit diagram and let us assume that the armature is revolving in a clockwise

direction, the same direction as the torque developed by the current. Because of rotation, the

armature conductors are cutting the lines of force of the field, thus generating voltages in the

armature conductors. Application of Fleming's right-hand rule shows that the direction of this

induced voltage is away from the observer on the left, and toward the observer on the right; that

is, the direction of the induced voltage is opposed to the direction of current flow. In sum then, in

any DC motor, rotation of the armature induces a voltage in the armature circuit which opposes

the flow of the current that causes the rotation. Because the direction of the voltage is counter to

the applied voltage, it is called counter electromotive force.

3. DC Series Motors: High Starting Torque but No Load Operation: -

Direct current (D.C.) series motors get their name from the way their armature and fieldwindings are connected together: in a series circuit. This type of connection gives a D.C. series

motor the following characteristics:

High Starting Torque No Load Operation Poor Speed Regulation

They are widely used for starting heavy, industrial, high torque loads such as cranes, hoists,elevators, trolleys and conveyors, but are also used for automobile starters. The primary

disadvantage of D.C. series motors is they cannot operate safely in an unloaded condition.

4. Construction: -

The basic components of a D.C. series motor are the armature, field windings, brush assembly,

frame, end bells and bearings. The armature is the rotating component of the motor and is made

of a steel shaft with notched laminations that the armature windings are wound on. On one end of

the shaft is the commutator, which consists of copper segments insulated from each other. Abrush assembly holds the electrically conductive, carbon graphite brushes, which slide on the

commutator segments and provide a means to connect the D.C. power supply to the rotating

commutator. The commutator and brushes function as an electro-mechanical switch that changesthe direction of current flow in the armature as it rotates. The field windings or magnet is a coil

and laminated pole assembly powered by the same D.C power supply as the armature. To correct

for armature reaction, interpoles are used to shift the neutral magnetic plane to eliminate brusharcing. The motor frame is a circular, steel structure that mechanically supports the field poles.
http://www.ohioelectricmotors.com/dc-series-motors-high-starting-torque-but-no-load-operation-ill-advised-595http://www.ohioelectricmotors.com/dc-series-motors-high-starting-torque-but-no-load-operation-ill-advised-595

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The end bells enclose all the components of the motor and are bolted onto the frame. Bearings

are pressed into the end bells to provide free movement of the armature.

Fig 7 24v dc series motor

5. Operation: -

Motor action governs the operation of a D.C. series motor and states that a current-carrying coil

will generate a magnetic field and if this coil is placed in another magnetic field, a force or

torque will be exerted on the coil. This torque will be proportional to both the current in the coiland the strength of the magnetic field it is placed within. The D.C. series motors armature(rotating component) is the previously mentioned current-carrying coil and the field winding(stationary component) of the motor is the other magnetic field. So, when the armature and field

windings are energized by a D.C. power supply, current will flow through these windings andgenerate their respective magnetic fields and will be magnetically positioned in such a manner to

cause torque. But this torque will only be sustained if the magnetic relationship of the armature

and field are maintained. This is accomplished by the commutator, which switches the current

flow and reverses the armatures magnetic polarity every time the commutator segment passesthrough a brush, causing the armature to be attracted to the stationary field magnet, thus

sustaining unidirectional torque or rotation.

6. Characteristics: -

To understand the proper application of D.C. series motors, one must understand the

characteristics of torque, speed and armature current relative to load changes. In D.C. seriesmotors, the entire armature current (Iarmature) passes through the series field windings so the

magnetic flux () produced is proportional to armature current:

Flux Iarmature

The torque produced will be proportional to the product of flux and armature current:

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Torque (Flux ) Iarmature

Since Flux Iarmature and Torque (Flux ) Iarmature, it follows that the Torque will be

proportional the square of Iarmature. In other words, in formula form:

Torque Iarmature2

This means that when a D.C. series motor is first started, very high torque will be producedbecause armature resistance is low, CEMF is zero and the total D.C. supply voltage will drive

current through the armature. This armature current would be unimpeded, causing a very high

torque. This characteristic makes D.C. series motors ideal for applications requiring high starting

torque.

While torque is proportional to the square of the armature current, motor speed is inversely

proportional to armature current. Thus, the torque-speed characteristic of a D.C. series motor is:

Speed 1/T

This characteristic means that as the load on the motor increases, the armature current willincrease and the torque will increase causing the motor speed to decrease. Hence, D.C. series

motors have poor speed regulation because they are load dependent. It also means that as the

load decreases, torque decreases and speed increases. At no load, the motor speed would ramp to

an extremely high level that could ultimately destroy the motor. This runaway condition wouldprove to be a personal safety hazard as well.

7. Applications: -

D.C. series motors are ideal for large loads and industrial applications that require high startingtorque. In addition, they have poor speed regulation thats load dependent and exhibit an unstablerunaway condition when unloaded. Hence, D.C. series motors should never be used where the

loads are intermittent, change frequently, or frequently cycle on/off. For example, a water pumpdrive that runs constantly and requires only small adjustments to maintain the flow rate would be

a good application for a series motor. Conversely, a pump that cycle frequently to maintain a

tank water level wouldnt.

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SENSORS

A sensor (also called detector) is a device that measures a physical quantity and converts it into

a signal which can be read by an observer or by an instrument. For example, a mercury-in-glassthermometer converts the measured temperature into expansion and contraction of a liquid which

can be read on a calibrated glass tube. A thermocouple converts temperature to an output voltagewhich can be read by a voltmeter. For accuracy, most sensors are calibrated against knownstandards.

1. Use

Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) andlamps which dim or brighten by touching the base. There are also innumerable applications forsensors of which most people are never aware. Applications include cars, machines, aerospace,

medicine, manufacturing and robotics.

A sensor is a device which receives and responds to a signal. A sensor's sensitivity indicates howmuch the sensor's output changes when the measured quantity changes. For instance, if the

mercury in a thermometer moves 1 cm when the temperature changes by 1 C, the sensitivity is1 cm/C (it is basically the slope Dy/Dx assuming a linear characteristic). Sensors that measure

very small changes must have very high sensitivities. Sensors also have an impact on what they

measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools theliquid while the liquid heats the thermometer. 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. Technological progress allows more and more sensors to be manufactured on a

microscopic scale as micro sensors using MEMS technology. In most cases, a microsensorreaches a significantly higher speed and sensitivity compared with macroscopic approaches.

2. OPERATING PRINCIPLES FOR PHOTOELECTRIC

SENSORS: -

3.These sensors use light sensitive elements to detect objects and are made up of an emitter

(light source) and a receiver. Four types of photoelectric sensors are available.

Direct Reflection - emitter and receiver are

housed together and use the light reflected

directly off the object for detection. In the

use of these photocells, it is important tobear in mind the color and the type of

surface of the object. With opaque surfaces,

the sensing distance is affected by the color

of the object. Light colors correspond to the

maximum distances and vice versa. In the

case of shiny objects, the effect of the

surface is more important than the color. The
http://en.wikipedia.org/wiki/Mercury-in-glass_thermometerhttp://en.wikipedia.org/wiki/Mercury-in-glass_thermometerhttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Voltmeterhttp://en.wikipedia.org/wiki/Calibrationhttp://en.wikipedia.org/wiki/Standard_%28metrology%29http://en.wikipedia.org/wiki/Tactile_sensorhttp://en.wikipedia.org/wiki/Microscopic_scalehttp://en.wikipedia.org/wiki/Microelectromechanical_systemshttp://en.wikipedia.org/wiki/Macroscopichttp://en.wikipedia.org/wiki/Macroscopichttp://en.wikipedia.org/wiki/Microelectromechanical_systemshttp://en.wikipedia.org/wiki/Microscopic_scalehttp://en.wikipedia.org/wiki/Tactile_sensorhttp://en.wikipedia.org/wiki/Standard_%28metrology%29http://en.wikipedia.org/wiki/Calibrationhttp://en.wikipedia.org/wiki/Voltmeterhttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Mercury-in-glass_thermometerhttp://en.wikipedia.org/wiki/Mercury-in-glass_thermometer

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sensing distance in the technical data is

related to matte white paper.

Reflection with Reflector - emitter and

receiver are housed together and require a

reflector. An object is detected when it

interrupts the light beam between the sensor

and reflector. These photocells allow longer

sensing distances, as the rays emitted are

almost totally reflected towards the receiver.

Polarized Reflection with Reflector -

similar to Reflection with Reflector, these

photocells use an anti-reflex device. The use

of such a device, which bases its

functioning on a polarized band of light,

offers considerable advantages and secure

readings even when the object to be sensed

has a very shiny surface. They are not in the

technical data affected by random

reflection. .

Thru Beam - emitter and receiver are housed separately and detect an object when it

interrupts the light beam between the emitter and receiver. These photocells allow for the

longest distances.

Light On / Dark On Types Of Output: For the photocell, the same terminology as inductive

and capacitive sensors is used: NO =normally open, NC = normally closed. This refers to the

state of the unit in the absence of the product to be sensed. In the case of photocells, light on /dark on is used. In the case of the direct reflection types, NO is light on and NC is dark on.

For the other types, NO is dark on and NC is light on.

Sensing Distance (Sn): The space in which it is possible to sense an object. In the case of

direct reflection types, it is the maxi-mum distance between the photocell and the object. In

the case of reflector or barrier types, it is the distance between the unit and the reflector or

between units.

Power Supply: The supply voltage range that sensor will operate at.

Power On Delay: This is the time lapse between providing power and the operation of the

output. This is to avoid unwantedswitching when the unit is powered.

Power Drain: The amount of current required to operate a sensor.

Voltage Drop: The voltage drop across a sensor when driving the maximum load.

Switching Current (Max): The amount of continuous current allowed to flow through the

sensor without causing damage to thesensor. It is given as a maximum value.

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Short Circuit Protection: Protection against damage to a sensor if the load becomes shorted.

Operating Frequency: The maximum number of on/off cycles that the device is

capable of in one second. According to EN50010.

Light Immunity: The maximum limit of an incandescent light or sunlight. Beyond this

limit, the photocell may not work correctlydue to interference on the receiver.

18 mm Plastic, DCFEATURES:

Low cost

LED function indicators

Short circuit & reverse polarity protection

Pre-wired cable or connector modelsCompliant to the EMC directive

Protection degree IP67: dust tight and protection from the effects of immersion

Fig 9 dc photoelectric sensor

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Fig10 wiring of dc photoelectric sensor

INSTRUCTIONS FOR THE PROGRAMMING AND ADJUSTMENT

TRIMMER FOR THE SENSING RANGE ADJUSTMENT: The photocell is supplied with max

sensing range with the trimmer totally rotated in the clockwise direction. The sensitivity reduces

by rotating the trimmer in the counterclockwise direction. SWITCH NPN/PNP: The photocell issupplied with the switch in P (PNP output). To change to NPN turn the switch to N in the

counterclockwise direction WARNING! Do not carry out the switching when the photocell ispowered. LED - OPERATION INDICATOR: This LED is on when the object to be detectedenters the sensing range of the photocell giving output signals

NOTE! Program the photo cell to NPN or PNP function before applying powerNOTE! It is recommended that the proper tool be used to rotate the trimmer and the switch to

avoid damage

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18 mm Plastic, ACFEATURES:

Plastic housing

Programmable output NO/NC

Sensitivity adjustment standard

LED function indicator20-250 VAC operating voltage

Pre-wired cable or connector modelsCompliant to the EMC directive

Protection degree IP67: dust tight and protection from the effects of immersion

Fig 13 ac photoelectric sensor

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WIRING: -

Fig 14 wiring of ac photoelectric sensor

3. Characteristics Curve: -

Fig 15 characteristics curves

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RELAYS

A relay is an electrically operated switch. Many relays use an electromagnet to operate a

switching mechanism mechanically, but other operating principles are also used. Relays are usedwhere it is necessary to control a circuit by a low-power signal (with complete electrical isolation

between control and controlled circuits), or where several circuits must be controlled by onesignal. The first relays were used in long distance telegraph circuits, repeating the signal comingin from one circuit and re-transmitting it to another. Relays were used extensively in telephone

exchanges and early computers to perform logical operations.

A type of relay that can handle the high power required to directly control an electric motor is

called a contactor. Solid-state relays control power circuits with no moving parts, instead using a

semiconductor device to perform switching. Relays with calibrated operating characteristics and

sometimes multiple operating coils are used to protect electrical circuits from overload or faults;in modern electric power systems these functions are performed by digital instruments still called

"protective relays".

1. Basic design and operation: -

A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core, an iron

yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one

or more sets of contacts (there are two in the relay pictured). The armature is hinged to the yokeand mechanically linked to one or more sets of moving contacts. It is held in place by a spring so

that when the relay is de-energized there is an air gap in the magnetic circuit. In this condition,

one of the two sets of contacts in the relay pictured is closed, and the other set is open. Other

relays may have more or fewer sets of contacts depending on their function. The relay in thepicture also has a wire connecting the armature to the yoke. This ensures continuity of the circuit

between the moving contacts on the armature, and the circuit track on the printed circuit board(PCB) via the yoke, which is soldered to the PCB.

When an electric current is passed through the coil it generates a magnetic field that activates the

armature and the consequent movement of the movable contact either makes or breaks(depending upon construction) a connection with a fixed contact. If the set of contacts was closed

when the relay was de-energized, then the movement opens the contacts and breaks the

connection, and vice versa if the contacts were open. When the current to the coil is switched off,the armature is returned by a force, approximately half as strong as the magnetic force, to its

relaxed position. Usually this force is provided by a spring, but gravity is also used commonly in

industrial motor starters. Most relays are manufactured to operate quickly. In a low-voltage

application this reduces noise; in a high voltage or current application it reduces arcing.

When the coil is energized with direct current, a diode is often placed across the coil to dissipate

the energy from the collapsing magnetic field at deactivation, which would otherwise generate avoltage spike dangerous to semiconductor circuit components. Some automotive relays include a

diode inside the relay case. Alternatively, a contact protection network consisting of a capacitor

and resistor in series (snubber circuit) may absorb the surge. If the coil is designed to beenergized with alternating current (AC), a small copper "shading ring" can be crimped to the end
http://en.wikipedia.org/wiki/Electrichttp://en.wikipedia.org/wiki/Switchhttp://en.wikipedia.org/wiki/Electromagnethttp://en.wikipedia.org/wiki/Contactorhttp://en.wikipedia.org/wiki/Solid-state_relayshttp://en.wikipedia.org/wiki/Moving_partshttp://en.wikipedia.org/wiki/Protective_relayhttp://en.wikipedia.org/wiki/Coilhttp://en.wikipedia.org/wiki/Magnetic_corehttp://en.wikipedia.org/wiki/Magnetic_reluctancehttp://en.wikipedia.org/wiki/Armature_%28electrical_engineering%29http://en.wikipedia.org/wiki/Spring_%28device%29http://en.wikipedia.org/wiki/Printed_circuit_boardhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Arcinghttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Voltage_spikehttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Snubberhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Snubberhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Voltage_spikehttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Arcinghttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Printed_circuit_boardhttp://en.wikipedia.org/wiki/Spring_%28device%29http://en.wikipedia.org/wiki/Armature_%28electrical_engineering%29http://en.wikipedia.org/wiki/Magnetic_reluctancehttp://en.wikipedia.org/wiki/Magnetic_corehttp://en.wikipedia.org/wiki/Coilhttp://en.wikipedia.org/wiki/Protective_relayhttp://en.wikipedia.org/wiki/Moving_partshttp://en.wikipedia.org/wiki/Solid-state_relayshttp://en.wikipedia.org/wiki/Contactorhttp://en.wikipedia.org/wiki/Electromagnethttp://en.wikipedia.org/wiki/Switchhttp://en.wikipedia.org/wiki/Electric

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of the solenoid, creating a small out-of-phase current which increases the minimum pull on the

armature during the AC cycle.[1]

A solid-state relay uses a thyristor or other solid-state switching device, activated by the control

signal, to switch the controlled load, instead of a solenoid. An optocoupler (a light-emitting

diode (LED) coupled with a photo transistor) can be used to isolate control and controlledcircuits

2. 24V DC 8 Pin Base Relay: -

Fig 16 8 Pin Relay

Fig 17 8 Pin Relay base
http://en.wikipedia.org/wiki/Relay#cite_note-0http://en.wikipedia.org/wiki/Relay#cite_note-0http://en.wikipedia.org/wiki/Relay#cite_note-0http://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Optocouplerhttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Photo_transistorhttp://en.wikipedia.org/wiki/Photo_transistorhttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Optocouplerhttp://en.wikipedia.org/wiki/Thyristorhttp://en.wikipedia.org/wiki/Relay#cite_note-0

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SWITCHES

In electronics, a switch is an electrical component that can break an electrical circuit,

interrupting the current or diverting it from one conductor to another.

The most familiar form of switch is a manually operated electromechanical device with one ormore sets ofelectrical contacts. Each set of contacts can be in one of two states: either "closed"meaning the contacts are touching and electricity can flow between them, or "open", meaning the

contacts are separated and the switch is non-conducting. The mechanism actuating the transition

between these two states (open or closed) can be either a " toggle" (flip switch for continuous"on" or "off") or "momentary" (push-for "on" or push-for "off") type.

A switch may be directly manipulated by a human as a control signal to a system, such as acomputer keyboard button, or to control power flow in a circuit, such as a light switch.

Automatically operated switches can be used to control the motions of machines, for example, to

indicate that a garage door has reached its full open position or that a machine tool is in a

position to accept another work piece. Switches may be operated by process variables such aspressure, temperature, flow, current, voltage, and force, acting as sensors in a process and used to

automatically control a system. For example, a thermostat is a temperature-operated switch used

to control a heating process. A switch that is operated by another electrical circuit is called arelay. Large switches may be remotely operated by a motor drive mechanism. Some switches are

used to isolate electric power from a system, providing a visible point of isolation that can be

pad-locked if necessary to prevent accidental operation of a machine during maintenance, or toprevent electric shock.

1. Switch In circuit theory

In electronics engineering, an ideal switch describes a switch that:

has no current limit during its ON state has infinite resistance during its OFF state has no voltage drop across the switch during its ON state has no voltage limit during its OFF state has zero rise time and fall time during state changes switches without "bouncing" between on and off positions

Practical switches fall short of this ideal, and have resistance, limits on the current and voltage

they can handle, etc. The ideal switch is often used in circuit analysis as it greatly simplifies the

system of equations to be solved, however this can lead to a less accurate solution.

2. Contacts: -

In the simplest case, a switch has two conductive pieces, often metal, called contacts, connected

to an external circuit, that touch to complete (make) the circuit, and separate to open (break) the

circuit. The contact material is chosen for its resistance to corrosion, because most metals form

insulating oxides that would prevent the switch from working. Contact materials are also chosen
http://en.wikipedia.org/wiki/Electronicshttp://en.wikipedia.org/wiki/Electrical_componenthttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electromechanicalhttp://en.wikipedia.org/wiki/Electrical_contacthttp://en.wikipedia.org/wiki/Light_switchhttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Thermostathttp://en.wikipedia.org/wiki/Relayhttp://en.wikipedia.org/wiki/Rise_timehttp://en.wikipedia.org/wiki/Fall_timehttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Electric_circuithttp://en.wikipedia.org/wiki/Corrosionhttp://en.wikipedia.org/wiki/Electrical_insulationhttp://en.wikipedia.org/wiki/Oxidehttp://en.wikipedia.org/wiki/Oxidehttp://en.wikipedia.org/wiki/Electrical_insulationhttp://en.wikipedia.org/wiki/Corrosionhttp://en.wikipedia.org/wiki/Electric_circuithttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Fall_timehttp://en.wikipedia.org/wiki/Rise_timehttp://en.wikipedia.org/wiki/Relayhttp://en.wikipedia.org/wiki/Thermostathttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Light_switchhttp://en.wikipedia.org/wiki/Electrical_contacthttp://en.wikipedia.org/wiki/Electromechanicalhttp://en.wikipedia.org/wiki/Electric_currenthttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Electrical_componenthttp://en.wikipedia.org/wiki/Electronics

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on the basis of electrical conductivity, hardness (resistance to abrasive wear), mechanical

strength, low cost and low toxicity.[3]

Sometimes the contacts are plated with noble metals. They may be designed to wipe against each

other to clean off any contamination. Nonmetallic conductors, such as conductive plastic, are

sometimes used. In order to prevent the formation of insulating oxides, a minimum wettingcurrent may be specified for a given switch design.

3. NO Push Button: -

Fig 20 NO Push Buttons

4.

NC Push Button: -

Fig 21 NC Push Buttons
http://en.wikipedia.org/wiki/Electrical_conductivityhttp://en.wikipedia.org/wiki/Hardness_%28materials_science%29http://en.wikipedia.org/wiki/Wear#Abrasive_wearhttp://en.wikipedia.org/wiki/Strength_of_materialshttp://en.wikipedia.org/wiki/Strength_of_materialshttp://en.wikipedia.org/wiki/Toxicityhttp://en.wikipedia.org/wiki/Switch#cite_note-2http://en.wikipedia.org/wiki/Switch#cite_note-2http://en.wikipedia.org/wiki/Switch#cite_note-2http://en.wikipedia.org/wiki/Electroplatinghttp://en.wikipedia.org/wiki/Noble_metalhttp://en.wikipedia.org/wiki/Designhttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Wetting_currenthttp://en.wikipedia.org/wiki/Wetting_currenthttp://en.wikipedia.org/wiki/Wetting_currenthttp://en.wikipedia.org/wiki/Wetting_currenthttp://en.wikipedia.org/wiki/Plastichttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Designhttp://en.wikipedia.org/wiki/Noble_metalhttp://en.wikipedia.org/wiki/Electroplatinghttp://en.wikipedia.org/wiki/Switch#cite_note-2http://en.wikipedia.org/wiki/Toxicityhttp://en.wikipedia.org/wiki/Strength_of_materialshttp://en.wikipedia.org/wiki/Strength_of_materialshttp://en.wikipedia.org/wiki/Wear#Abrasive_wearhttp://en.wikipedia.org/wiki/Hardness_%28materials_science%29http://en.wikipedia.org/wiki/Electrical_conductivity

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Indicators

Indicators are often used to show On and Off status of a device. Generally red indicators are used

to indicate off status and green indicators are used to show on status of a device. In our projectwe have used two indicators one is red and one green. Green one shows movement of the

conveyor and red one shows filling process. The both indicators are of 24v dc. Both theindicators are connected in relay at the pin number 4. These indicators have dielectric property of2.5 KV and insulation resistance greater than 2M ohms. Brightness is greater than 60 cd/m2. It

can withstand for a temperature range of -25 to 55 degree Celsius and relative humidity up to

98%

Fig 22 Indicators

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