CERTIFICATE

This is to certify that the project work entitled “STUDY AND

DESIGN OF CALIBRATION PROCEDURE FOR

INSTRUMENTS USED IN PRODUCTION” work carried by

HARSHIT PANDEY, Department of Electronics Engineering, IPS College of Tech & Mgmt is completed by him during 30 days training period in his B.Tech. 4th year under my guidance and direction.

Place: Gwalior Faculty guide:- Mr. Asim Dubey (HOD of Electronics) Date: …………………….

ACKNOWLEDGEMENT

Research is a very high concept; it brings to test our patience, vigor, and dedication. Every result arrived marks the beginning for a higher achievement. My training in the same interest is just a drop in the ocean.

No work can be turned as a single person show. It needs the help of friends, colleagues and guidance of experts in achieving something new and worth full.

It was a remarkable and memorable experience undergoing the training at Cadbury, Malanpur.

I am extremely grateful to Mr. Sharat C. Naik (Factory Manager), of Cadbury India Ltd. who allowed me to perform my summer training.

I am deeply grateful to Mr. Asim Dubey (HOD Electronics) for his worthy guidance, valuable suggestions and timely help that enabled me to complete this summer training successfully. Also I am thankful to Ms. Chandrika Joshi of H.R. division for her guidance and help.

Finally I would express my sincere thanks to all the staff of Cadbury India Ltd.

CONTENTS

1. Certificate

2. Acknowledgement

3. Company and Plant Overview

4. Introduction to confections

5. Manufacturing process

6. H.T. Yard Design

7. Calibration

8. Sensors8.1Temperature sensors8.2Pressure sensors8.3Weight sensors8.4Metal detectors

9. Variable frequency ac drive

10. Programmable logic controller (PLC)

11. PID controller

COMPANY AND PLANT OVERVIEW

GENERAL INTRODUCTION TO THE COMPANY

Cadbury Schweppes international began as one man venture in Birmingham. UK in 1824, a young entrepreneur JOHN CADBURY set-up a shop in Birmingham to sell, among other things, a cocoa concoction of his own. From such a modest beginning, it has grown to be the leading manufacturer of food, beverages and confectionery in the UK. It has revolutionized eating habits world wide. The name Cadbury has become synonymous with cocoa products in many countries. Cadbury Schweppes employs people around the world over and has 50 principles, subsidiary and associated companies in 21 countries.

In India Cadbury was set up as a trading in 1947 and gradually began in a small way by processing of imported chocolates and Bournvita at Colaba, Mumbai. In 1948, the company was incorporated as Cadbury Fry (India) Private Ltd. In 1956, the operations shifted from Colaba to Cadbury house. The first Indian manufactured chocolates and Bournvita moved out of the Cadbury house in 1956. With further growth entire operations were moved to our new locations at Thane. They now have manufacturing facilities at other location such as Induri, Malanpur, and some third party units.

MAJOR COMPETITORS

In India, the major competitors of Cadbury India Ltd. In the field of chocolates are Nestle, Amul, Campo, etc. In éclair type of chocolates the major competitors are nestle and campo. However, the competitors in the world of gems are successfully maintained its monopoly in marketing gems.

MAJOR CUSTOMERS

Almost every human being in India, either he/she is a child, a teenager, an adult or an old person, comes into the huge list of customers of company’s product. However, gems are more targeted towards the lower age group. Seeing the attractive packaging and various shining colors of them can also sense it.

VISIONS OF CADBURY INDIA LTD

Cadbury India will continue to maintain its leadership position in the chocolate confectionary market as well as achieve a strong national presence in the food drinks sections by:

Expanding the confectionery/drinks market through broadening consumers appeal and geographical expansions.

Growing our share of food drink business. Focusing on cost competitiveness and productivity.

GENERAL INFORMATION ABOUT THE MALANPUR PLANT

In 1989, the company started manufacturing operations from its third and newest factory at Malanpur near Gwalior. Using the most modern state of art technology, the unit manufactures’ éclairs, gems, five star, perk, and picnic.

Location: Plot No. 25, Malanpur Industrial Area, Malanpur, Distt. Bhind. Tel. No. : 07539-83803, 83804

The malanpur unit is a cost- based unit, only to manufacture the products and send them to sales and marketing department in Mumbai. For effective and speedy communication, Malanpur is also attached with c.c. mail network with other Cadbury locations including head office.

Parent company: Cadbury Schweppes International, UKTotal land: 101170.55 sq. meters Turn over: 284 (nos.)

There are following products which are made in Cadbury India ltd.:

1) five star2) éclairs3) wafer perk (picnic)4) gems

INTRODUCTION TO CONFECTIONS

Confection (i.e. a candy) can be divided into two broad categories: those in which sugar is the principle ingredient and those which are based on chocolate. Difference in sugar - based candies depends largely on manipulation of sugar to achieve special textural effects. This is accomplishing primarily by controlling the proceeding state of crystallization of the sugar and sugar moisture ratio. Examples of sugar type confections include nougats, fondants, caramels, toffees and jellies. Examples of chocolate based confection are chocolate covered confection, chocolate panned, chocolate bars and chocolate covered and creams ingredients, including milk products, egg white, food acids, gums, starches, emulsifiers, flavors, nuts, fruits and others are used in candy making. Chocolate is not only one of the principle ingredients used by the confectioners. But its widely enjoyed flavor properties make it a favorite material of bakers; ice-cream producers and other food manufacturers.In its many forms, chocolate may be consumed as a beverage, syrup, a flavoring, a coating, or a confection in itself.

CHOCOLATE:

Definition: Chocolate means a homogeneous product obtained by an adequate process of manufacturing from a mixture of one or more ingredient namely: Cocoa beans, Cocoa nibs, cocoa mass, cocoa press cake and cocoa dust including fate reduced cocoa powder with or without addition of sugar, cocoa butter, milk solid including milk fat and non-prohibited flavoring agent. The chocolate shall not contain any vegetable fat other than cocoa butter. Chocolate has two major distinguishing characteristics: its flavor and its texture. Although many different flavors of chocolate exist, all must be free from objectionable tastes. A primary feature of the texture is that it must be solid at a normal room temperature of 20-25˚C and yet melt rapidly in the month at 37˚C giving a liquid that feels smooth to the tongue.

INGEDIENTS:

The basic ingredient required for chocolate manufacture are cocoa nibs, cocoa liquor, sugar, other sweetness, cocoa butter, butter fat, milk powder, milk crumbs and emulsifiers.

1) COCOA BEANS: Chocolate and related products began with cocoa beans. These are fermented micro-biologically enzymatically, result in the removal of adhering pulp and mucous, kills the germ of the bean and modifies the flavor and color of the bean. After it beans are dried to about 7% moisture to improve the self life.

2) COCOA NIBS AND COCOA LIQUOR:These beans are roasted to further develop flavor and color. They are then passed through winnowing machine to remove seed coats and separate the germs, the mulled and germ free beans are called nibs. The nibs are passed through the various types of mills where they are torn apart and ground, releasing fat from the cells. The heat of grinding melt the fat and ground the nibs acquire a liquid consistency. The liquid discharge from the mill is known as chocolate liquor.

3) COCOA BUTTER: The edible fat obtained from sound cocoa beans before and after roasting they exhibit a very complex crystallization system as a result of different glycerides present. It is polymorphic which means it will crystallize in several different forms according to how the liquid fat is solidified.

4) EMULSIFIER:The most popular emulsifier is lecithin used to reduce viscosity and save cocoa butter, since chocolate is very fine dispersion of chocolate particle in a fat phase. The solid is composed of sugar and composed cocoa material in the case of dark chocolate. In milk chocolate, solid particles are present in addition to milk fat, the latter being included in the fat phase. In the first process of chocolate production, the fat is all in the liquid stage, but in the latter stage the chocolate used for molding or enrobing is in a tempered condition. Chocolate with a working viscosity suitable for molding or enrobing can be prepared with a much lower cocoa butter content lecithin is present.

When lecithin is added higher temperature process is possible without viscosity change. It also improves bloom resistance and gloss.

5) FLAVOR: Some of the flavor of the chocolate particularly dark chocolate, comes from the blend of beans used with milk chocolate, milk caramelisation play an important part.

6) REWORK:This is the name given to reprocess the chocolate bars and confectionary. It is possible to reclaim miss- happen chocolate units in the form of pastes, syrups or cumb, and utilizes then as part of the basic ingredients of new batches of chocolate.

MANUFACTURING PROCESS

PERK XL FLOWCHART

LECITHIN, FAT, CCS,ETC.

BATTER MIXING WHEAT FLOUR

SPRAYING OF BATTER

BAKING IN OVEN TO FORN WAFER

COOLING ON ARCH CONVEYOR

CREAM SREADING

LAMINATION TO FROM BOOK

BOOK COOLING

WAFER CUTTING

ROPE CONVEYOR

CREAM MAKING

REWORK BLENDER (BCH)

METAL DETECTION

COOLING OF BARS

ENROBING

ECLAIRS FOWCHART:

PACKAGING AUTO WRAPPERS

AUTO DISTRIBUTION

ALIGNMENT OF BARS

PACKAGING

MILK POWDER, WATER, GMS, SALT EV, VANASPATI

FOOD MILK MAKING

HOLDING VESSEL

PRE- DISSOLVER

PREMIX MAKING

SUGAR, GLUCOSE, REWORK

CONTINUOUS COOKER

COOLING

METAL DETECTOR CHECK

WRAPPING

CRÈME FILLING

UNIT FORMATION

ROPE FORMING

BATCH FORMING

COOLING

FIVE STAR CRUNCHY FLOW CHART:

SORTING

PACKING IN BOX

FFS

TRANSFER TO WAREHOUSE

FOAMING AGENT

FOAMING SYRUP BEATING T.S. COOKING

SUGAR SOLUTION

FRAPPE

MIXING CREME

NOUGATINE

COOLING OF PREMIX

PRE-DISSOLVING OF PREMIX

PREMIX

E- MILK

CARAMEL

CHOCOLATE

CUTTING

COOLING

SHEETING

PACKAGING

METAL DETECTION

ENROBING

COOLING

GEMS FLOWCHART:

CHOCOLATE TANK

MICROVERK

COOLING TUNNEL

SIEVE

STORED IN CRATES FOR 8 HOURS

ROUNDING

PANNING

GUM COATING MAIDA COATING SUGAR COATING COLOR COATING

STORED IN CRATES FOR 8 HOURS

SORTING

ADDITION OF CAPOL IN BAFFLE PAN

ADDITION OF QUICK GLANCE

STORED IN CRATES FOR 4 HOURS

AUTO WRAPPER

METAL DETECTOR

POUCH

C- BOXES

H.T. YARD DESIGN

WORKING PROCEDURE FOR ISOLATION OF THE LINE:

A) After individual isolation and up to the transformer:

1) First cut-off the all load from MPEB and take the load on D.G. 2) Draw out the ABC of each transformer in LT room. 3) Switch of the MOCB 1, 2 & 3 / VCB of transformer no. 1, 2 &

3 and provided the tag of “Men At Work”.4) Isolate the isolator no. 1, 2 & 3.5) Provided the earthing rod on the H.T. conductor isolator no. 1,

2 & 3.

B) From GOD switch to all transformers:1) First cut-off the all load from MPEB and take the load on D.G. 2) Draw out the ACB of each transformer in L.T. room and

provided the tag “Men at Work”.3) Switch of the MOCB 1, 2 & 3 of transformer no. 1, 2 and 3 and

provide “ MEN AT WORK”. 4) Isolate the isolator no. 1, 2 and 3. 5) Provided the earthing rod on the H.T. conductor isolator no. 1,

2 and 3 (all and where we are going to work).6) Switch of the VCB no. 4 if we are going to the work at

incoming side.7) Isolate the GOD switch if we are going at incoming side.8) Provided the earthing on the H.T. conductor between GOD

switch VCB no. 4.

C) For work before GOD switch:

1) First intimate to authorized MPEB person and take the written permit for doing the maintenance activity and ensure that MPEB person has switched off the line from MPEB substation.2) Provided the earthing rod before GOD switch.3) Follow all the points written in heading (B).

Lightening arrester:Device used on electrical power systems to protect the insulation on the system from the damaging effect of lightening. Metal oxide varistors (MOVs) have been used for power system protection since the mid 1970s. The typical lightening arrester also known as surge arrester has a high voltage terminal and a ground terminal. When a lightening surge or switching surge travels down the power system to the arrester, the current from the surge is diverted around the protected insulation in most cases to earth.

Circuit Breaker:

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and by interrupting continuity, to immediately discontinuous electrical flow. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.

High Voltage Circuit Breaker:

Electrical power transmission networks are protected and controlled by high- voltage breakers (for 72.5 KV or max.). High voltage breakers are nearly always solenoid- operated, with current sensing protective relays operated through current transformers. In substitution the protection relay scheme can be complex, protecting equipment and buses from various types of overload or ground/earth fault. High- voltage breakers are broadly classified by the medium used to extinguish the arc.

Bulk oil Minimum oil Air blast Vacuum SF6

Over current relay:

An “over current relay” is a type of protective relay which operates when the load current exceeds a preset value. The ANSI device number is 50 for an instantaneous over current (IOC), 51 for a time over current (TOC). In a

typical application the over current relay is connected to a current transformer and calibrated to operate at or above a specific current level. When the relay operates, one or more contacts will operate and energize to trip (open) a circuit breaker.

CALIBRATION

Calibration is a comparison between measurements - one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device.

The device with the known or assigned correctness is called the standard. The second device is the unit under test (UUT), test instrument (TI), or any of several other names for the device being calibrated.

Basic calibration process:

The calibration process begins with the design of the measuring instrument that needs to be calibrated. The design has to be able to "hold a calibration" through its calibration interval. In other words, the design has to be capable of measurements that are "within engineering tolerance" when used within the stated environmental conditions over some reasonable period of time. Having a design with these characteristics increases the likelihood of the actual measuring instruments performing as expected.

The next step is defining the calibration process. The selection of a standard or standards is the most visible part of the calibration process. Ideally, the standard has less than 1/4 of the measurement uncertainty of the device being calibrated. When this goal is met, the accumulated measurement uncertainty of all of the standards involved is considered to be insignificant when the final measurement is also made with the 4:1 ratio.

Ideally the calibration value of 100 units would be the best point in the gage's range to perform a single-point calibration. Depending on the device, be a calibration point. Or zero may be resettable by the user-there are several variations possible. Again, the points to use during calibration should be recorded.

All of the information above is collected in a calibration procedure, which is a specific test method. These procedures capture all of the steps needed to perform a successful calibration.

This exact process is repeated for each of the standards used until transfer standards, certified reference materials and/or natural physical constants, the

measurement standards with the least uncertainty in the laboratory, are reached. This establishes the traceability of the calibration.

After all of this, individual instruments of the specific type can finally be calibrated. The process generally begins with a basic damage check. More commonly, a calibration technician is entrusted with the entire process and signs the calibration certificate, which documents the completion of a successful calibration.

SENSORS

A) TEMPERATURE SENSORS:

Temperature Sensors:1) RTD Pt 100 2) Thermocouple3) Thermometer4) Pyrometer5) Thermistor

RTD Pt 100:

RTD Pt 100 is RESISTANCE TEMPERATURE DETECTOR that uses platinum whose resistance is 100 Ω at 0˚C. As the temperature increases its resistance also increases. It is basically a temperature sensitive resistor. It is a positive temperature coefficient device, which means that the resistance increases with the temperature. The resistive property of the metal is called its resistivity. The resistive property defines length and cross sectional area required to fabricate an RTD of a given value. The resistance is proportional to the length and inversely proportional to the cross sectional area. RTDs can be of 2 wire, 3 wire or 4 wire. The most common are the 3 wire RTDs. The two wires are for making connections while the other wires are there to compensate the resistance of the connecting wires. There can be single channel or multi channel RTDs.

Temperature measurement and Calibration of RTDs.:

The probe of the RTD in which Pt 100 is there is inserted in the vessel or the tank in which the liquid is there whose temperature is to be determined. The resistance of the Pt 100 will change according to the temperature of the liquid. The resistance of the Pt 100 can be determined using a calibrator or a multi meter. A standard chart is there by which the temperature of the liquid can be determined. When the RTD is connected to a controller, the controller needs to be calibrated according to it. The connections are made and the RTD is connected to the controller. The Pt 100 is inserted into the liquid and this makes an arm or the wheat stone bridge (in the controller). Now as the temperature of the liquid changes, the resistance of the Pt 100 changes this unbalances the wheat stone bridge. The detector in the wheat stone bridge is so calibrated that it directly shows the temperature of the liquid for the given change in the resistance of the Pt 100.

PYROMETER:

A pyrometer is a non contacting device that intercepts and measures thermal radiation, a process known as pyrometry. This device can be used to determine the temperature of an object’s surface.A pyrometer has an optical system and detector. The optical system focuses the thermal radiation onto the detector. The output signal of the detector is relaed to the thermal radiation or irradiance j* of the target object through the Stefan- boltzmann constant and the emissivity ε of the object.

j* = εσT4

This output is used to infer the object’s temperature. Thus, there is no need for direct contact between the pyrometer and the object, as there is with thermocouple and RTDs.They are used to calculate the temperature of moving parts where a RTD or a thermocouple cannot be directly fitted.

Testing and Calibration of a Pyrometer:Pyrometer is a 5 wire device. The white and the brown wire is connected to the positive and negative terminal of the power supply respectively. The output is taken from the yellow and the green wire. The black wire is screened. The power is supplied is supplied to the pyrometer. The pyrometer is fitted in front of the moving device whose temperature is to be determined. The output can be determined directly by using a calibrator or a multi meter, or can be displayed directly on a controller. Every pyrometer comes with a conversion relation like by which the mV read from the calibrator can be directly converted to the degree Celsius. Eg. IMPAC Infrared GmbH infartherm IN 3000 , the output is 10mV/˚C. The range of temperature that can be measured is from 0 to 300˚C. A 24 V dc power is supplied to it. For calibration purposes, a master instrument is whether through which the temperature of the object is known accurately and then the temperature of the object is determined using the pyrometer to be calibrated. Thus the error in the pyrometer can be determined and can be accounted for.

THERMISTORS: Thermistor symbol

NTC thermistor, bead type, insulated wires

Thermistors are thermally sensitive resistors whose prime function is to exhibit a large, predictable and precise change in electrical resistance when

subjected to a corresponding change in body temperature. Negative temperature coefficient (NTC) thermistors exhibit a decrease in electrical resistance when subjected to an increase in body temperature and positive temperature coefficient (PTC) thermistors exhibit an increase in electrical resistance when subjected to an increase in body temperature. When a thermistor is used in a circuit where the power dissipated within the device is sufficient to cause “self heating”, the thermistor’s body temperature will be dependent upon the thermal conductivity of its environment as well as its temperature. Thermistors are “self heated” for use in application such as liquid level detection, air flow detection and thermal conductivity measurement. They differ from RTDs in that the material used in a thermistor is generally a ceramic or polymer while RTD use pure metals. The temperature response is also different; RTDs are useful over larger temperature ranges, while thermistors typically achieve a higher precision within a limited temperature range (-90˚C to 130˚C).

They are more accurate i.e, shows a large change in resistance for small changes in temperature. Their response is in KΩ. They are also used for protection purposes. It is a 2 wire device. Both the connecting wires are of same material unlike in a thermocouple.

THERMOCOUPLE:

It is a two wire device, two wires are of different materials. Depending upon the type of material used in two wires many types of thermocouples are available in the market. One end of each wire is joined and is called the hot junction. This junction is kept in the tank containing the material whose temperature is to be determined. The other end of each wire is connected to a temperature controller. This junction is called the cold junction and is kept at room temperature. Now as the temperature of the tank changes, a temperature difference is developed between the hot and cold junction due to which an emf is induced in the thermocouple. This induced emf is proportional to the temperature difference between the hot and cold junction. Thermocouples are mainly used for high temperature measurements. Temperature measurement and Calibration of thermocouple:

1. Check the level of water in the bath. Connect the apparatus to the Power supply.

2. Turn on the water bath by switching the main switch (1) as shown in the figure.

3. Keep the set-in switch (8) depressed and set the temperature to desired level (30 deg C to start) by turning the knob(6) and observing the display(7). Release the switch(8) after setting the temperature. In normal mode, the temperature shown on the digital display is the actual temperature of the bath (TB) against which the thermocouple sensor is to be calibrated.

4. Connect the ends of the thermocouple to the digital multimeter (MM) and set the multimeter to read in millivolts DC.

5. Dip one junction of the thermocouple in the thermo-bath liquid and wait for few minutes for it to reach the steady state (i.e. the reading on the MM steadies down except the last digit). Be careful to hold (tape) the sensor wire away from the circulator's propeller!

6. Note down the digital MM reading in millivolts (EMM) and repeat the steps 3 through 6 in steps of 5 degrees from 30 to 60 degrees Celsius.

7. As mentioned in the theory, the multimeter reading corresponds to the difference in temperature between the surroundings (room) and the bath. To calibrate the thermocouple, we have to take the room temperature into consideration to get the absolute value of temperature measured. Find the equivalent millivolt value for the room temperature from the corresponding Thermocouple table (ERM). Then, add that millivolt value, corresponding to the room temperature, to every multimeter reading (EMM). Tabulate the values.

Procedure for Calibration of Temperature Controller

Connect the Resistance Decade Box to the Input of temperature Controller.

Feed the resistance to the Controller as per the Specified Chart. Verify the Corresponding readings of the Controller against the

resistance fed as per the Specified chart. If the reading is out of the Acceptance Range, then calibrate the

Temp. Controller by adjusting the pots of the Controller. Re- verify the accuracy after rectification Take the set of at least four readings preferably covering the operating

range of Temperature Controller. Put the Calibration Sticker on the Temp. Controller mentioning the

Calibration Done Date and the Next Calibration Due Date.

B) PRESSURE SENSORS:

Diaphragm:

A diaphragm pressure gauge is a device that uses a diaphragm with a known pressure to measure pressure in a fluid. It has many different uses, such as monitoring the pressure of a canister of gas, measuring atmospheric pressure, or recording the strength of the vacuum in a vacuum pump.

Basic mechanics:

The diaphragm has a flexible membrane with two sides. On one side is an enclosed capsule containing air or some other fluid at a predetermined pressure. The other side can be left open to the air or screwed into whatever system the gauge is meant to measure. The diaphragm also attaches to some sort of meter, which shows how high the pressure is.

Detecting Pressure:

A fluid in contact with a flexible membrane pushes on that membrane, bending it. The pressure is a measure of how hard it pushes. When the outside preference is low, the pressure bends the membrane out. As the outside pressure increases, it pushes back on the membrane, bending it back the other way. By measuring how far the membrane bends, the gauge can detect the outside pressure.

Measuring the Pressure:

There are many different ways to measure the pressure from a dynamic pressure gauge. One of the simplest ones is to attach a needle to the gauge. When the pressure increases, it pushes on the needle, moving it up and down along a dial which shows the pressure. Another way is to use an electric resistance strain gauge. An electric resistance strain gauge uses a long strip of an electric resistor – a device that resists the flow of electricity. The resistor is attached to the diaphragm. As the diaphragm bends it stretches out the resistor, increasing the resistance. The resistor has an electric current running through it. The more the diaphragm bends and increases the resistance, the more the current drops. By measuring the electric current, the gauge can determine how far the diaphragm has bent, and thus, how much pressure the outside air is creating.

BOURDON TUBES:

A bourdon gauge uses a coiled tube, which, as it expands due to pressure increases causes a rotation of an arm connected to the tube. In 1849, the bourdon tube pressure gauge was patented in france by Eugene Bourdon. The pressure sensing element is a closed coiled tube connected to the chamber or pipe in which pressure is to be sensed. As the gauge pressure increases the tube will tend to uncoil, while a reduced gauge pressure will cause the tube to coil more tightly. This motion is transferred through a linkage to a gear train connected to an indicating needle. The needle is

presented in front of a card face inscribed with the pressure indications associated with particular needle deflections. In a barometer, the bourdon tube is sealed at both ends and the absolute pressure of the ambient atmosphere is sensed. Differential bourdon gauges use two bourdon tubes and a mechanical linkage that compares the readings.

VACUUM GAUGE:

Instruments used to measure pressure are called pressure gauges or vacuum gauges.

A manometer could also be referring to a pressure measuring instrument, usually limited to measuring pressures near to atmospheric. The term manometer is often used to refer specifically to liquid column hydrostatic instruments.

A vacuum gauge is used to measure the pressure in a vacuum --- which is further divided into two subcategories: high and low vacuum (and sometimes ultra-high vacuum). The applicable pressure range of many of the techniques used to measure vacuum have an overlap. Hence, by combining several different types of gauge, it is possible to measure system pressure continuously from 10 mbar down to 10−11 mbar.

Procedure for Calibration of Vacuum GAUGE

we require a vacuum pump We require mercury filled manometer Check no vacuum leakages Hold the vacuum for 5 min check zero scale of manometer connect the manometer to vacuum pump

Connect the vacuum gauge to be calibrated check zero reading of vacuum gauge then starts the vacuum pump When manometer reading reaches to max. 760 mm Hg check the reading at vacuum gauge under calibration adjust the span screw if required check different readings through complete scale by dropping the

vacuum from pump

Procedure for Calibration of PRESSURE GAUGE

we require a dead weight tester or a comparator, fill compressed oil in the dead weight tester remove the air lock of dead weight tester then install pressure gauge which is to be calibrate, on dead weight

tester compare the reading of pg with weight which is put on deadweight

tests check zero & span of pg in full range, adjust zero & span screw respectively, if requires

C) WEIGHT SENSORS:

LOAD CELLS: A load cell is a transducer which converts force into a measurable electrical output. Although there are may varieties of load cells, strain gage based load cells are the most commonly used type.

Operating principle:

Load cell designs can be distinguished according to the type of output signal generated ( pneumatic, hydraulic, electric) or according to the way they detect weight ( bending, shear, compression, tension, etc. )

Strain Gage Load cells:

They convert the load acting on them into electrical signals. The gauges themselves are bounded onto a beam or structural member that deforms when weight is applied. In most cases, four strain gages are used to obtain maximum sensitivity and temperature compensation. Two of the gauges are usually in tension and two in compression, and are wired with compensation adjustments. When weight is applied, the strain changes the electrical resistance of the gauges in proportion to the load. Other load cells are fading into obscurity, as strain gage load cells continue to increase their accuracy and lower their unit costs.

Styles of load cells;

1) Compression load cell2) S- beam load cell3) Platform and single point load cell4) Low profile load cell5) Compression/ Tension load cell 6) Bending Beam load cell7) Canister load cell

Procedure for Calibration of Weighing Scale

Put the Standard Calibrated Weight on the Weighing Scale. Log the Actual Reading of the Scale against the Standard Calibrated

weight. If the reading of the Scale is out of the Acceptance range then take

necessary action to rectify it. Re- verify the accuracy after rectification Take the set of at least four readings for different weights preferably

covering the operating range of Weighing Scale. Put the Calibration Sticker on the Scale mentioning the Calibration

Done Date and the Next Calibration Due Date.

D) METAL DETECTORS:

A metal detector is a device which responds to metal that may not be readily apparent.

The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. If a piece of electrically conductive metal is close to the coil, eddy currents will be induced in the metal, and this produces an alternating magnetic field of its own. If another coil is used to measure the magnetic field (acting as a magnetometer), the change in the magnetic field due to the metallic object can be detected.

The first industrial metal detectors were developed in the 1960s and were used extensively for mining and other industrial applications. Uses include de-mining (the detection of land mines), the detection of weapons such as knives and guns, especially in airport security, geophysical prospecting, archaeology and treasure hunting. Metal detectors are also used to detect foreign bodies in food, and in the construction industry to detect steel reinforcing bars in concrete and pipes and wires buried in walls and floors.

Procedure for Calibration of Metal detector:

1) put the program in auto learn product 2) pass the material through the metal detector3) weight for auto learn complete4) pass the standard metal sample 1. 1.5mm ferrous 2. 2.0 mm non ferrous 3. 2.4mm ss5) Check detection of standard metal piece6) If no detection, then adjust the gain, & phase angle of metal detector7) Then again pass standard metal piece.8) Check dumping of metal piece in to bucket.

VARIABLE FREQUENCY AC DRIVE

Small variable frequency drive

A variable-frequency drive (VFD) is a system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor.[1][2][3] A variable frequency drive is a specific type of adjustable-speed drive. Variable-frequency drives are also known as adjustable-frequency drives (AFD), variable-speed drives (VSD), AC drives, micro drives or inverter drives. Since the voltage is varied along with frequency, these are sometimes also called VVVF (variable voltage variable frequency) drives.

Variable-frequency drives are widely used. In ventilation systems for large buildings, variable-frequency motors on fans save energy by allowing the volume of air moved to match the system demand. They are also used on pumps, conveyor and machine tool drives.

The main power components of an AC drive have to be able to supply the required level of current and voltage in a form the motor can use. The controls have to be able to provide the user with necessary adjustments such as minimum and maximum speed settings, so that the drive can be adapted to the user's process. Spare parts have to be available and the repair manual has to be readable. It's nice if the drive can shut itself down when detecting either an internal or an external problem. It's also nice if the drive components are all packaged in a single enclosure to aid in installation but that's about it.

The real action in an AC variable frequency drive system is in the motor. All loads moved by electric motors are really moved by magnetism. The purpose of every component in a motor is to help harness, control, and use magnetic force. When applying an AC drive system it helps to remember you are actually applying magnets to move a load. To move a load fast does not require more magnets, you just move the magnets fast. To move a heavier load or to decrease acceleration time (accelerate faster) more magnets (more torque) are needed. This is the basis for all motor applications.

ALLEN BRADLEY: Power Flex 40 Adjustable Frequency AC Drive:

Control I/O Terminal Designations:-

No. Signal Default Description Param.

R1 Relay N.O. Fault Normally open contact for output relay

A055

R2 Relay Common -

Common for output relay

R3 Relay N.C Fault Normally closed contact for output relay

A055

Analog Output Select DIP Switch

0-10V Sets analog voltage to either voltage or current. Setting must match A065(analog Out Sel.)

Sink/Source DIP Switch

Source(SRC) Inputs can be wired as Sink(SNC) or Source(SRC) via DRP Switch setting

01

Stop Coast The factory jumper or a normally closed input must be present for the drive to start

P036

02

Start/Run FWD

Not Active

Command comes from integral keypad from default. To disable reverse operation see A095(Reverse Disable)

P036,P037

03

Direction/Run REV

Not Active

P036,P037,A095

04

Digital common

- For digital inputs. Electronically isolated with digital inputs from analog I/O and opto outputs

05

Digital input 1

Preset Freq

Program with A051(Digital ln1 Sel.)

A051

06

Digital input 2

Preset Freq

Program with A052(Digital ln2 Sel.)

A052

07

Digital input 3

Local Program with A053(digital ln3 Sel.)

A053

08

Digital input 4

Jog Forward

Program with A054 (Digital ln 4 Sel.)

A054

09

Opto Common

- For Opto coupled outputs. Electronically isolated with opto outputs from analog I/O and digital inputs.

11

+24V DC - Refenced to Digital Common. Drive supplied power for digital inputs. Maximum output current is 100mA.

12

+10V DC - Referenced to Analog Common. Drive supplied power for 0-10V potentiometer.Maximum output current is 15 mA.

P038

13

+-10 V ln(2) Not active

For external 0-10V (unipolar) or ±10V (bipolar) input supply (input impedance = 100k ohm) or potentiometer wiper.

P038, A051-A054, A123, A132

14

Analog Common

- For 0-10V ln or 4-20 mA ln. Electronically isolated with analog inputs and outputs from digital I/O and opto outputs.

1 4-20mA In(2) Not For external 4-20 mA input P038,

5 Active supply(input impedance =250 ohms)

A051-A054, A132

16

Analog Output

OutFreq 0-10

The default analog output is 0-10V. To cover t to a current value, change the Analog Output Select DIP Switch to 0-20mA. Program with A065 [Analog Out Sel]. Max analog value can be scaled with A066 [Analog Out High]. Maximum Load: 4-20mA = 525 ohm (10.5V)0-10V = 1k ohm (10mA)

A065, A066

17

Opto Output 1

MotorRunning

Program with A058 [Opto Out1 Se]

A058, A059, A064

18

Opto Output 2

At Frequency

Program with A061 [Opto Out2 Se]

A061, A062, A064

19

RS485 (DSI) Shield

_ Terminal should be connected to safety ground - PE when using the RS485 (DSI) communications port

P= parameter, A= advanced parameter

PROGRAMMABLE LOGIC CONTROLLER

PLC means Programmable Logic Controller. It is a class of industrially hardened devices that provides hardware interface for input sensors and output control element. The field I/P include element like limit switches, sensors, push button and the final control elements like actuator, solenoid/control valves, drives, hooters etc. PLC senses the input through I/P modules, processes the logic through CPU and memory and gives output through output module.

PLC can be used in almost all industrial application solutions right from small machine to large manufacturing plants. Even it caters applications of redundant systems at critical process plants.

Role of PLC in automation:PLC plays most important role in automation. All the monitoring as well as the control actions is taken by PLCs. PLC senses the input through I/P modules, processes the logic through CPU and memory and gives output through output module.

Role of CPU:This component acts as a brain of the system.CPU consists of arithmetic logic unit, program memory, process image memory, internal timers and counters, flags.It receives information from I/P device, makes decisions depending upon the information and logic written and sends information through the O/P devices. The CPU’s are distinguished with following features. Memory capacity, instruction set supported, communication option, time required to execute the control program.

Role of Power supply in PLC system:Power supply provides system power requirement to processor, I/O and communication modules. Typically the power supply has input voltage 120 V – 230 V AC or 24 V DC and back plane output current 2 A to 5 A at 5 V DC.

Role of Rack or Chassis in PLC system:

It is a hardware assembly, which houses the processor, communication and I/O modules. It does following functions:

Power distribution Containment of I/O modules Communication path between I/O module and CPU.

The chassis are available in different slots in various PLC systems. Additional chassis can be connected using chassis interconnecting cable.

Role of I/O modules:Electronic plug in units used for interfacing the I/P and O/P device in the machine or process to be controlled.I/P module receive data from i/p devices (Pushbutton, Switches, and Transmitters) and send it to processor. The O/P module receives data from processor and sends it to output device (Relay, Valves).

Digital/Discrete: - Sends and receives On/Off signal Analog: - Sends and receives variable input or output signals.

Role of EEPROM Memory Module:-This module is inserted into processor system for maintaining a copy of project (PLC program). This is helpful in case memory corruption or extended power loss.

Role of Communication Module:-Communication modules are used for communication between external hardware or software. The hardware can be PLC same or other make), Controller, I/O module, smart transmitters. The software can be SCADA software, MIS system or programming software.

Analog Input Module:-An I/O module contains circuits that convert analog input signals to digital values that can be manipulated by the processor the signals for pressure, flow, level, temperature transmitters are connected to this module. Typically the input signal is 4-20mA, 0-10V.

Analog Output Module:-An I/O module that contains circuits that output an analog dc signal proportional to a digital value transferred to the module from the processor.

By implication, these analog outputs are usually direct (i.e., a data table value directly controls the analog signal value).

Universal Analog Input Card:-Normally these are different cards for different signals. But in universal input card the same channels can be configured for RTD, Thermocouple,Current or voltage input.

Scan cycle of PLC:-PLC’s cycle follows following path cycle of PLC

Input Image Updating Process Logic Execution Output Updating

Scan Time in PLC:-Scan time is the time required to read the I/P, process the logic and update the output in one cycle.

Programming In PLC’s:-Every PLC manufacture have their own software or programming the PLC. For example Siemens uses Semantic S7 Manager, Allen Bradley uses RS Logix and Modicums uses PLC pro programming software. The programming language used is Ladder Logic (LD), Statement List (STI),Functional Block Diagram(FBD),Sequential Foundation Chart(SFC),Instruction List (IL) etc.

Ladder Diagram:-This is as programming language which expresses a program as a series of “coils” and “contacts”, simulating the operation of electrochemical relay.The resultant program is the equivalent of an equation, which is executed continuously in a combinatorial manner. The advantage of this language is the familiarity many electricians have with the simple operation of relays. Disadvantages include the complexity of large, cross-connected programs, and the difficulty of expressing such non-binary functions as motion control and analog I/P.

Redundancy:-The capacity to switch from primary equipment to standby equipment automatically without affecting the process under control. Redundancy means provision for standby module. In case of failure of one module is

running process, the standby module takes over. Hot means the changeover of control from active to standby process or in less than one scan time.

Need of Redundancy:-In critical process, it is important to run the plant without failure. In such case it is important to have redundancy such that even in one system fails the redundant system can take care without affecting plant.

Types of Redundancy:-

CPU redundancy: In case of CPU failure, the standby failure takes care of the plant.

Power Supply redundancy: In case the power supply fails the standby power supply takes care of the situation.

Communication:-Multiple communication channels are provided to take care of communication failure.

I/O Redundancy: Multiple I/O channels are provided to take care of input or output failure.

Components of Redundant PLC System:-Typical component on Schneider Redundant PLC’sThe backplane used is either 4 slot or 6 slot with

Power Supply Controller with built-in Mudbug Plus and Mudbug ports Optional dual cable Modbus Plus Optional fiber optic Modbus Plus CHS Hot Standby module Dual cable Remote I/O Head

The master and standby configuration must be identical.

Commonly used Instructions in PLCs:-

Examine if Closed(XIC):- | | Examines if the bit is ON condition. If the bit is ON the instruction is true.

Examine if Open(XIO):- |/| Examines if the bit is in OFF condition.If the bit is OFF the instruction is true.

One short rising(OSR):- [OSR] When the conditions preceding the instruction is true,makes the one run for one program scan.

Note retentive Output instruction:-Output Entergies (OTE):- () -- If the rung is true, it turns on the bit.If the

rung goes or a power cycle occurs the bit turns off.

Retentive Output instructionOutput Latch(OTL):-(L):- If the rung is true, turns ON a bit.The bit

stays ON until the rung containing an OUT with the same address goes true.

Output Latch(OUT):-(U)- If the turn is true,turns OFF a bit. The bit stays OFF until the rung containing an OTL with the same address goes true.

Timers:-

Timers and counters are used to control operation based on time or number of events.

Types of timers:TON-(Timer ON delay) An output instruction that can be used to

turn an output ON or OFF after the timer has been timing fir a preset time interval.

TOF-(Time OFF delay) An output instruction used to turn an output ON or OFF after its rung has been off for a preset time interval.

RTO-(Retentive Timer) An output instruction that can be used to turn an output ON or OFF after timer has been timing for a preset time interval.Once it has begin timing,it holds the count of time even when the rung continuity is lost.

Programming logic Controller-Allen Bradley

PLC ranges available in Rockwell are:- Pico:Non modular small PLCs Micrologix 1000,1200and 1500Series SLC:SLC 5/01,5/02,5/03….. Control Logix Flex Logic and Soft PLC

Difference between Micro Logic and SLCMicrologix1.Has limited 1/0 Large capacity of 1/02.Use DFI only Use PID,DH+

The software used with AB:-For Pico soft for Pico PLC programmingRs Logix 500 for Micrologix and SLC PLCs programming RS Logix 5000 for Control Logix PLCs programming

SCADA-RS View earlier Control View

Use of RS Linx Software:-

RS Linux software is used to perform following tasks. Configure communication drivers View configured drivers and active nodes Enable communication tasks such as uploading, downloading, going

online, updating firmware and sending messages

Use of RS Logix Software:-

RS Logix is a PLC programming software. It contains all the instructions needed for PLC programming. We can develop the program, download/upload the program, work on line/off line and force the I/Os using the software.RS Logix 500 is ised for Micrologix and SLCsRS Logix 5000 is used for Control Logix PLCs

The files that are created in PC for RS Logix PLC program:Data at speed up to 10 megabits per second. Ethernet is used as the underlying transport vehicle by several upper-level protocols, including TCP/IP.

Latency in Communication:The delay time between the end of one communication and the start of another. During this time, the processes associated with the communication are hung up and continue The latency to be minimum.

Criteria of Distinguishing Communication Protocols:The protocols are distinguished with following specifications

No. of nodes supported, total network length, speed of communication.

Comparison between various protocols used with AB:-DH+ DH485 Device Net Control Net

Baud rate max 230.4 kbits/s 19.2kbit/s 500 kbit/s 5 Mbit/s

No. of max. nodes

64 32 64 99

Network Length 3.048 Km 1.2Km 0.487Km 30 Km

Programmable Logic Controller-Siemens

Siemens has broadly 3 PLC ranges i.e. Siemens S7 200,300 and 400Software Used with Siemens:-For S7 200 PLC programming MicroFor S7 300 and 400 system: Semantic S7 managerThe SCADA software used by siemens is Win CC. Earlier Siemens use to supply COROS LS/B

Components of Siemens S7 300 Series PLC system:-CPUs(312 IFM,313,314,IFM,314,315,2DP,318)Single Modules(SM):Digital I/O (SM321,322,323),Analog I/O(331/332/334)Function modules (FM) ex Positioning Modules, Closed LoopCommunication Processor ex CP 342-5 DP for ProfibusInterface module-For interconnecting individual racks (IM 360/361,IM 365 S/R)

Communication Protocol Used in Siemens:-Multi-Point Interface (MPI):Data Transfer-187,5 kbits to 15 Mbit/s,Distance-50 m without RS 485 repeater/ 10 Km wit repeaterNumber of nodes-up to 32

Profibus:Data transfer-12 Mbit/sDistance-23 Km with fibre optic cableNumber of nodes-up to 125Blocks Used in Siemens:-Simantic S7 manager uses DB,OB,FC,PBand FB

PID CONTROLLER

A bl

ock diagram of a PID controller

A proportional–integral–derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control systems – a PID is the most commonly used feedback controller. A PID controller calculates an "error" value as the difference between a measured process variable and a desired setpoint. The controller attempts to minimize the error by adjusting the process control inputs. In the absence of knowledge of the underlying process, PID controllers are the best controllers.[1] However, for best performance, the PID parameters used in the calculation must be tunedaccording to the nature of the system – while the design is generic, the parameters depend on the specific system.

The PID controller calculation (algorithm) involves three separate parameters, and is accordingly sometimes called three-term control: the proportional, the integral and derivative values, denoted P, I, and D. The proportional value determines the reaction to the current error, the integral value determines the reaction based on the sum of recent errors, and the derivative value determines the reaction based on the rate at which the error has been changing. The weighted sum of these three actions is used to adjust the process via a control element such as the position of a control valve or the power supply of a heating element. Heuristically, these values can be interpreted in terms of time: P depends on

the present error, I on the accumulation of past errors, and D is a prediction of future errors, based on current rate of change.[2]

By tuning the three constants in the PID controller algorithm, the controller can provide control action designed for specific process requirements. The response of the controller can be described in terms of the responsiveness of the controller to an error, the degree to which the controller overshoots the setpoint and the degree of system oscillation. Note that the use of the PID algorithm for control does not guarantee optimal control of the system or system stability.

Some applications may require using only one or two modes to provide the appropriate system control. This is achieved by setting the gain of undesired control outputs to zero. A PID controller will be called a PI, PD, P or I controller in the absence of the respective control actions. PI controllers are fairly common, since derivative action is sensitive to measurement noise, whereas the absence of an integral value may prevent the system from reaching its target value due to the control action.

PID controller Theory:

The PID control scheme is named after its three correcting terms, whose sum constitutes the manipulated variable (MV). Hence:

where Pout, Iout, and Dout are the contributions to the output from the PID controller from each of the three terms, as defined below.

Proportional term:

Plot of PV vs time, for three values of Kp (Ki and Kd held constant)

The proportional term (sometimes called gain) makes a change to the output that is proportional to the current error value. The proportional response can be adjusted by multiplying the error by a constant Kp, called the proportional gain.

The proportional term is given by:

where

Pout: Proportional term of outputKp: Proportional gain, a tuning parametere: Error = SP − PVt: Time or instantaneous time (the present)

A high proportional gain results in a large change in the output for a given change in the error. If the proportional gain is too high, the system can become unstable (see the section on loop tuning). In contrast, a small gain results in a small output response to a large input error, and a less responsive (or sensitive) controller. If the proportional gain is too low, the control action may be too small when responding to system disturbances.

Integral term:

Plot of PV vs time, for three values of Ki (Kp and Kd held constant)

The contribution from the integral term (sometimes called reset) is proportional to both the magnitude of the error and the duration of the error. Summing the instantaneous error over time (integrating the error) gives the accumulated offset that should have been corrected previously. The accumulated error is then multiplied by the integral gain and added to the

controller output. The magnitude of the contribution of the integral term to the overall control action is determined by the integral gain, Ki.

The integral term is given by:

where

Iout: Integral term of outputKi: Integral gain, a tuning parametere: Error = SP − PVt: Time or instantaneous time (the present)τ: a dummy integration variable

The integral term (when added to the proportional term) accelerates the movement of the process towards setpoint and eliminates the residual steady-state error that occurs with a proportional only controller. However, since the integral term is responding to accumulated errors from the past, it can cause the present value to overshoot the setpoint value (cross over the setpoint and then create a deviation in the other direction).

Derivative term:

Plot of PV vs time, for three values of Kd (Kp and Ki held constant)

The rate of change of the process error is calculated by determining the slope of the error over time (i.e., its first derivative with respect to time) and multiplying this rate of change by the derivative gain Kd. The magnitude of

the contribution of the derivative term (sometimes called rate) to the overall control action is termed the derivative gain, Kd.

The derivative term is given by:

where

Dout: Derivative term of outputKd: Derivative gain, a tuning parametere: Error = SP − PVt: Time or instantaneous time (the present)

The derivative term slows the rate of change of the controller output and this effect is most noticeable close to the controller setpoint. Hence, derivative control is used to reduce the magnitude of the overshoot produced by the integral component and improve the combined controller-process stability. However, differentiation of a signal amplifies noise and thus this term in the controller is highly sensitive to noise in the error term, and can cause a process to become unstable if the noise and the derivative gain are sufficiently large. Hence an approximation to a differentiator with a limited bandwidth is more commonly used. Such a circuit is known as a Phase-Lead compensator.

Summary of PID controller:

The proportional, integral, and derivative terms are summed to calculate the output of the PID controller. Defining u(t) as the controller output, the final form of the PID algorithm is:

where the tuning parameters are:

Proportional gain, KpLarger values typically mean faster response since the larger the error, the larger the proportional term compensation. An excessively large proportional gain will lead to process instability and oscillation.

Integral gain, Ki

Larger values imply steady state errors are eliminated more quickly. The trade-off is larger overshoot: any negative error integrated during transient response must be integrated away by positive error before reaching steady state.

Derivative gain, KdLarger values decrease overshoot, but slow down transient response and may lead to instability due to signal noise amplification in the differentiation of the error.