manual -ipc 7th semester

7/28/2019 Manual -IPC 7th Semester

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INSTRUMENTATION & PROCESS CONTROL

LAB MANUAL (7th Semester)

LAB INCHARGE:

Prof. Dr. Arshad Chughtai

FACULTY TEAM:

Ms. Rabya Aslam

Institute of Chemical Engineering & Technology

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Experiments List:

A. Calibration of Instruments:

1. Calibrate the given Bourdon Gauge using the Mercury Filled Manometer. Also find

out the span, error and accuracy of the bourdon gauge.

2. Calibrate and report the accuracy of the given Bourdon Gauge using Dead Weight

Tester.

3. Calibrate the Given Resistance Temperature Detector using the mercury filled

Thermometer.

4. Calibrate the given Thermocouple using Thermometer.

B. Process Analysis:

5. Find out the time constant of the given Mercury Filled Thermometer and also find

the response y(t) of the system when t =, t = 2, t = 3

6. Find out the time constant of the Liquid Level System

C. Control Loops:

7. Report the response and variations in the process variable PV( flow of water)output

in

i. Proportional Mode (P- mode) by giving the values of gain as 1.00, 0.6 and

1.6 while the output of controller set on 30 % i.e. set point = 30 %.

ii. Proportional Integral mode (PI mode) by giving the values of Reset time, as

0.1, 0.15 and 0.5 while the output of controller set on 30 %.

iii. Proportional Integral Derivative mode (PID mode) by giving the values of

rate minute as 1, 2, 3 while the output of controller set on to 30 %.

8. Study the response of the process variable (temperature) in the on-off algorithm.

Also plot the graph between time and temperature during heating and cooling.

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Table of Contents:

Contents Page no.

1. Calibration of Bourdon gauge using Manometer 4

2. Calibration of Bourdon gauge using dead weight tester 8

3. Calibration of RTD using thermometer 12

4. Calibration of thermocouple using thermometer 15

5. Time constant of thermometer 18

6. Time constant of liquid level system 22

7. Flow control loop 26

8. Temperature control loop 32

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Experiment # 1: Calibration of Bourdon Gauge using

Manometer

Objective:To calibrate the given Bourdon gauge using the Mercury Filled Manometer also report

the accuracy of the Bourdon gauge.

Apparatus:

Bourdon gauge

Mercury filled thermometer

Air compressor

Procedure:

Start the air compressor before performing the experiment.

Mercury level in the U-shaped manometer is checked.

The Manometer shows the value of the change in pressure by inches of mercury and Bourdon

gauge report the value of same pressure in psi or bar.

The readings of both the manometer i.e., inches of mercury and Bourdon gauge i.e., psi or

bar are noted after the alteration in the pressure by means of controlling valve.

The readings of manometer i.e., in inches of mercury are converted into psi by multiplying

with an appropriate factor.

The graph between manometer readings at X-axis and the Bourdon gauge reading at Y-axis

is plotted. A straight line at 45 form origin is drawn. The maximum difference between the

actual plotted line and the 45 line is the Span error.

Formulae Used:

1. Pressure Reading using Manometer

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=

c

airHg

g

hgP

)(

Where

Hg is density of Mercury

airis density of Air

h = difference in height between two limbs of manometer

2. Average Error

==

n

E

AvgError

n

i 1

Where

E = Error for ith observation

n = number of observations

3. Accuracy:

n

ValuedardS

ValueMeasuredValuedardS

ErrorX

n

i

=

==1

100tan

tan

%

Accuracy = X %

Bourdon Gauge is X % inaccurate

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Observations and calculations:

Density of Air = air= 1.2 kg/m3

Density of Mercury = Hg = 13,650 kg/m3

No. of

obs.

Gauge

Pressure

(kg/cm2)

Gauge Pressure

(X1)

(kPa)

Manometer

Reading, H

(inHg)

Differential

pressure

measured by

manometer

X2

(kPa)

Error

(X1-X2)

(kPa)

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RESULT:

Results

AccuracyRange

Average Error

Experiment # 2: Calibration of Bourdon Gauge Using Dead

Weight Tester

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Objective:

To calibrate and report the accuracy of the given Bourdon gauge, using dead weight tester.

Apparatus:

Bourdon gauge

Dead weight tester

Weights.

Working Principle:

The working principle of the above depicted Dead weight tester is based on Pascal

Law. This law states that if pressure is applied on a fluid at rest, the pressure is equally

distributed to all directions, i.e. one to the piston of the dead weight tester and the other to the

Bourdon gauge.

Procedure:

1. Initially the gauge which is to be calibrated is connected with the dead weight tester.

2. The lever is moved outward completely

3. After putting a pressure plate of suitable weight upon dead weight tester, the lever is

gradually moved outwards.

4. During closure of lever, Bourdon gauge showed increase in pressure. The piston is moved

inwards until the scale of Bourdon gauge stops with the jerk.

5. At that point Bourdon gauge reading is noted.

6. Again the same procedure is repeated right from the beginning by placing another

pressure plate on the top of already placed pressure plate.

7. The graph between dead weight tester reading on X-axis and Bourdon gauge reading on

Y-axis is plotted.

Formulae used:

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1. Accuracy:

n

ValuedardS

ValueMeasuredValuedardS

ErrorX

n

i

=

==1

100tan

tan

%

Accuracy = X % inaccurate

2. Average Error

==

n

E

AvgError

n

i 1

Where

E = Error for i

th

observationn = number of observations

Observations & Calculations:

Sr. No.

Pressure applied

by weights,

P1

Bourdon gauge

Reading

P2

Error,

E=P1-P2

kg/cm2 kg/cm2 kg/cm2

Calibration Curve:

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Result:

Results

Accuracy

Range

Average Error

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SUMMARYOF BOURDON GAUGE

Category Pressure Measuring Device

Working Principle Mechanical displacement due to pressure

on fluid.

Material of construction

Berylium

Copper

steel

chrome alloy steel

stainless steel

Accuracy 1-5% of full span

Limits of application Up to 100 MPa.

Advantages

Low cost with reasonable accuracy.

wide limits of application

can be used in harsh environment

Disadvantages

affected by shock and vibrations

have slow response time as compared to

bellow

Experiment # 3: Calibration of RTD

Objective:

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To calibrate the given Resistance Temperature Detector using the Mercury Filled

Thermometer.

Apparatus:

Resistance Thermometer (Platinum)

Beaker

Oil bath

Thermometer

Avometer

Procedure:

Initially the Avometer is standardized by joining the two ends of the wires of RTD to

Avometer and then wires are short circuited in order to set the pointer at zero.

The resistance thermometer is inserted in the oil beaker which already had the mercury

filled thermometer.

The oil in the beaker is heated and different sets of readings are taken for resistance and

the temperature for every five degree centigrade temperature rise.

Finally a graph between temperature and the resistance is plotted. The straight line drawn

showed the fitness of the resistance thermometer under consideration for the required

purpose.

Observations:

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Sr. No.Temperature

(C)

Resistance

(ohm)

Calibration Curve:

Summary Of RTD

Category Temperaturesensor

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Working Principle

Resistance of metal increase with increase

in temperature.

Material of construction Platinum

Nickel

Sensitivity 0.004/C to 0.005/C

Limits of application

Up to 650C for Platinum

Up to 300C for Nickel

Advantages

High accuracy.

Wide Range of application

Good reproducibility

Higher signal to noise ratio.

Can be used in radiation environment

Disadvantages

Slower response time

Expensive

Experiment # 4: Calibration of Thermocouple usingThermometer

Objective:

To calibrate the given Thermocouple with the help of Thermometer

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Apparatus:

Potentiometer

Thermocouple

Oil bath

Mercury filled Thermometer

Procedure:

1. The standardization of potentiometer is done, when the thermocouple is not connected to

it.

2. After connecting the thermocouple with potentiometer, the thermocouple and a mercury

filled thermometer are inserted into oil beaker.

3. The oil in beaker is heated up to 180 C then for every 5 C drop in temperature a

corresponding change in E.M.F. is noted via potentiometer.

4. The change in E.M.F. along with the change in temperature of the system is plotted on a

graph.

Observations & calculations:

No. of Obs.Temperature,

TE.M.F.

C mV

Calibration Curve:

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Summary of thermocouple

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Category Temperature Sensor

Working Principle SEEBECK effect


Chromel-Alumel

Copper-Constantan

Platinum,Rhodium-Platinum

Limits of application -100 to 1100C

Advantages

Low cost with reasonable accuracy.

Wide Range of application

Good reproducibility

Good accuracy

Disadvantages

Cannot be used for radiation environment

Low value of emf is corrupted with noise

Temperature is not exactly linear with emf

Thermocouple types

Type E- Type E (chromelconstantan)

Type K- Type K (chromel{90 percent nickel and 10

percent chromium}alumel)

Type J- Type J (ironconstantan)

Type N- Type N (NicrosilNisil)

Type R- Type R thermocouples use a platinumrhodium

alloy containing 13% rhodium

Type S- Type S thermocouples are of 90% Platinum and

10% Rhodium

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Experiment # 5: Time Constant of Mercury Filled

Thermometer

Objective: Determine the time constant of the given mercury filled thermometer dipped in an oil

bath.

Draw graph between Y(t)/A and t/ and report response Y(t) of the system

when t=, t=2, t=3.

Apparatus:

Two mercury filled thermometer

Oil bath

Heating device

Stop watch.

Procedure:

1. Initially the room temperature is noted.

2. The mercury filled thermometer is dipped in the oil bath which is placed on the heating

arrangement.

3. The whole arrangement is heated till the temperature of the bath is reached to 220C. The

attained temperature is maintained.

4. Another thermometer, whose time constant is to determine is dipped in the same oil bath

and the rise in temperature after every 5 seconds is noted along with time.

5. The required parameters are calculated and a graph between above mentioned quantities

is plotted.

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Observations and Calculations:

Room temperature= y(s) = CMaximum temperature for heater oil bath = y() = 220C

Amplitude = A = y() - y(s)

Sr. No

Time

t

Temperature

of

Thermometer

y(t),

Y(t)=

y(t)-

y(s)

Y(t)/

At/ = - ln(1- (Y(t)/A))

(sec) C C

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Response of system at when t=, t=2, t=3.

At t/ = 1,

Y(t)/A = 0.63 (From graph)

Y(t) = 0.63 x A C

Results:

Results

Time Constant (sec)

Response of System

Y(t) when t/ =

1C

Y(t) when t/ =

2C

Y(t) when t/ =

3C

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Summary of thermometer

Category Temperature Measuring Device

Working Principle Expansion of fluid with increase in

temperature.


Ordinary Soda Lime

Fused Quartz

Advantages of mercury

Hg is opaque.

Hg is good conductor.

It does not wet the glass surface

Limits of application

Up to 350C for mercury

Less than 120C for alcohol

Advantages

Low cost

Can be used easily.

Used as STANDARD equipment for

calibration of temperature sensors

Good accuracy

Disadvantages Cannot be used in industry for automatic

control.

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Experiment # 6: Liquid Level System

Objective:

Find the Time Constant of the given Liquid Level System, also report the effect of dia and

length of tube on time constant of system

Apparatus:

Storage tank,

Tubes (of certain lengths),

Beaker,

Scale

Stop watch.

Procedure:

1. A tube of certain length and diameter was fitted at the bottom of tank. Storage tank was

filled up to a certain level (say h1). A finger was put at the end of the tube so that no

water can flow.

2. Then a beaker was placed under the tube and the finger was removed from the lower end

of the tube. The water began to flow and at the same time, a stopwatch was operated and

the time for which the level of water fell to a certain height in the storage tank (say h2)

was noted. The volume of the water that fell into the beaker was measured.

3. The mean of height or level of water was also noted.

4. Diameter of Storage tank was also measured.

5. By drawing a graph of mean level of water (along X axis) vs. the flow rate(along Y-axis),

the resistance was noted.6. The time constant of the system can be noted by the formula.

Time Constant = Resistance x Storage Capacitance

7. The experiment was repeated by taking tubes of different length and diameter.

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Formulae Used:

1. Area of tank

A = cm2

Whered = diameter of tank

2. Time Constant:

= Rx A

Where

A = Area of Tank

R= Resistance to flow

3. Resistance (from graph):

Observations & Calculations:

Diameter of the storage tank = d cm

Area of the storage tank = A cm2

1. Length of tube = L1 cm

Serial #

Initial

level of

water(h1)

Final level

of water

(h2)

Mean Level

(H)

Volume

Time

of

flow

Flow rate

Q

1 in in in cm (ml) (sec) (ml/sec)

2 7.5 6.5 7

3 6.5 5.5 6

4 5.5 4.5 5

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5 4.5 3.5 4

6 3.5 2.5 3

7 2.5 1.5 2

From graph:

R=Resistance to flow =

Time constant:

= R A

Result were repeated for different tube lengths and diameters.

24

0

2

4

6

8

10

12

2 4 6 8 10 12

Flowrate,Q(ml/s)

Mean Level (cm)

Time Constant of Liquid Level System with tube oflength L1


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Results:

Results

Dia of tube = constant = d cm

Time Constant for L1 = 1



Length of tube = constant = L cm

Time Constant for d1 = 1



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7. The pump is still not started. When the pump is started immediately one person will

record the readings of magnetic flow transmitter and other person simultaneously

record the reading (maxima and minima)of the output displayed with reference to the

time i.e. readings can be taken after every 5 seconds or any other time which may be

suitable. Also observes how quickly the system stabilizes.

8. When set point is achieved and approximately oscillations are stopped then the pump

is to be stopped from the control panel switch. Same procedure is repeated for

different gain values (0.6, 1.6) and keeping other parameters constant.

Procedure:

Methodology adopted would be the same and the variables will have the following values: Gain = 0.6 for all the three inputs

Rate minute = 0.00 for all the three inputs

Reset min = 0.1, 0.15 and 0.5

Same procedure will be followed to develop the graph.

3) PID Mode

Procedure:

Methodology adopted would be the same and the variables will have the following values,

Gain = 0.6 for all the three inputs

Rate minute = 1, 2, 3

Reset min = 0.1 for all the three inputs

Same procedure will be followed to develop the graph..

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Block Diagram:

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Flow Diagram:

1. Storage Tank

2. Pump

3. Control Valve

4. Restriction Valve

5. Bottom valve

FT-1: Flow Transmitter

FC-1: Flow Controller

LC-2: Positioner

PI-1: Pressure gauge

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FT-2: Flow Transmitter (Magnetic)

2) PI mode

Proportional Controller

Set point=30%Plot Graph for all gains by taking time against x-axis and Controller Output across Y axis.

30

Tuning

ParametersGain = 0.6 Gain =1.0 Gain =1.6

Time

(s)

ControlledVariable

(%TO)

ControlledVariable

(%TO)

ControlledVariable

(%TO)

0

5

10

15

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Proportional Integral Derivative Controller:

Set point=30%

31

Tuning

Parameters

Gain = 0.6

Integral time=0.1

Gain =0.6

Integral time=0.15

Gain =0.6

Integral time=0.5

Time

(s)

ControlledVariable

(%TO)

ControlledVariable

(%TO)

ControlledVariable

(%TO)

0

5

10

15

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32

Tuning

Parameters

Gain = 0.6Integral time=0.1

Rate min=1

Gain =0.6Integral time=0.1

Rate min=2

Gain =0.6Integral time=0.1

Rate min=3

Time

(s)

Controlled

Variable

(%TO)

Controlled

Variable

(%TO)

Controlled

Variable

(%TO)

0

5

10

1520

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Experiment # 8: Temperature Control Loop

Objectives:

To study the response of the process variable (temperature) in the on-off

algorithm. Also plot the graph between time and temperature during heating and cooling.

Procedure:

1. Initially the water supply tube from the cooling element is connected to the main water

supply.

2. The outlet tube from the solenoid valve is connected to the drainage.

3. The process container is filled with water so as to cover the cooling element.

4. The electric power supply is connected.

5. The controller is set according to the following procedure.

6. The set point Select key is pressed until Algorithm is displayed.

7. The set point value is set to the required value (according to heating or cooling system)

8. For the above set point, note down reading of temperature against time.

9. Plot a graph b/w temperature (along y-axis and time (along x-axis) both for cooling and

heating process.

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During heating:-

Set Point=55oC

During Cooling:

Set Point=46.7 oC

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Sr no. Time (sec) Temperature (oC)

1. 5

2. 10

3. 15

4. 20

5. 25

6. 30

7. 35

8. 409. 45

10. 50


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Reference:

1. Coughanowr, D. R.:Process Systems Analysis and Control, 2nd ed., McGraw-Hill.

2. Fribance, A. E.: Industrial InstrumentationFundamentals,McGraw-Hill, 1962.

3. Luyben, W. L.: Process Modeling, simulation, and Control for Chemical Engineers,

3rd ed,McGraw-Hill, Inc., 1997.

4. Seborg, D. E. et al.:Process Dynamics and Control, 2nd ed, John Wiley & Sons, Inc.,

1989.

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Sr no. Time (sec) Temperature (oC)

1.2.

3.

4.

5.

6.

7.

8.

9.


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manual -ipc 7th semester

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