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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
Material of construction
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.
Material of construction
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
Time Constant for L2 = 2
Time Constant for L3 = 3
Length of tube = constant = L cm
Time Constant for d1 = 1
Time Constant for d2 = 2
Time Constant for d3 = 3
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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
34
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.
35
Sr no. Time (sec) Temperature (oC)
1.2.
3.
4.
5.
6.
7.
8.
9.
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