1. OE Laboratory 1

2. List of experiments
•
Calibration of following transducer
–
Wave probe
–
LVDT
–
Accelerometer
–
Pressure transducer
–
Load cell
–
Inclinometer
•
Gauge factor for resistance strain gauge
•
Data acquisition system

3. Writing the report
•
Student name and Reg. Number
•
Title
•
Aim
•
Apparatus required
•
Theory and working principle with figures
•
Procedure
•
Table of results
•
Plots
•
Conclusion
Hand written report

4. Expt1: Calibration of Wave Probe.

5. Expt1: Calibration of Wave Probe.
•
Apparatus
–
Wave probe, Amplifier, Height Gauge, Bucket of water
•
Purpose of wave probe
–
To measure the fluctuating water depth
•
Type of wave probe
–
Change in resistance
–
Change in capacitance
–
Ultrasonic wave probe
–
Change in conductivity
•
Working
–
Conductivity between two stainless steel electrodes changes with
change in water

6. Expt1: Calibration of Wave Probe.
•
Procedure
–
Fix the wave probe in the calibration set up
–
Connect the wave probe to the amplifier and to the multi-meter
–
With the help of amplifier node set the multi-meter reading to zero
–
Move wave probe (up/down) in side the water with the help of scale set up
and note the reading from multi-meter(volt)
–
Repeat the experiment for wave probe movement once downward then for
upward. Take the average of multi-meter reading for every matching scale
value.
–
Plot water depth versus volts and get the slope of the curve.
–
Slope of curve will give calibration constant in cm/volt.

7. Expt1: Calibration of Wave Probe.
S. No Wave Probe
position (cm)
Test No 1 (Volt) Test No 2 Test No 3
Up Down Avg Up Down Avg Up Down Avg
1 +15 -3.74 3.39 -3.39
2 +10 -2.49 -2.49 -2.49
3 +5 -1.26 -1.23 -1.24
4 0 -0.02 -0.02 -0.02
5 -5 1.21 1.22 1.215
6 -10 2.47 2.42 2.44
7 -15 3.39 3.39 3.39
Plot displacement Vs Volt and get the slope (cm/volt)

8. End of Experiment 1

9. Expt2: Calibration of Linear Variable Transformer
(LVDT)

10. Expt2: Calibration of Linear Variable Transformer
(LVDT)
•
Apparatus
–
LVDT, DC current supplier, Multi-meter, Height Gauge
•
Purpose of LVDT
–
To measure the time varying displacement in digital form
•
Working
–
Consists of one primary coil, two secondary coils and ferromagnetic
core
–
Secondary coils are connected to each other in series but in opposite.
–
Position of ferromagnetic core decides the amount of induced current
in secondary coils.

11. Expt2: Calibration of Linear Variable Transformer
(LVDT)•
Procedure
–
Connect the LVDT to DC voltage supplier and Multi-meter.
–
Voltage supplied to the LVDT is 15 to 30 volt.
–
Connect the other end (moving core) of LVDT to Height Gauge.
–
Adjust the height gauge such that red mark on moving core of LVDT should be just
visible
• This ensure that volt output from primary and secondary coils are balanced to show zero output
–
Make upward and downward reading zero in height gauge.
–
Move the height gauge by 10mm and note the reading in multi-meter
–
Repeat this procedure for upward and downward movement and take average

12. Expt2: Calibration of Linear Variable Transformer
(LVDT)
Gauge movement (mm) Measured output (volt)
upward Downward Average
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0

13. End of Experiment 2

14. Expt3: Gauge factor of resistance strain Gauge

15. Expt3: Gauge factor of resistance strain Gauge

16. Expt3: Gauge factor of resistance strain Gauge

17. Expt3: Gauge factor of resistance strain Gauge
•
Apparatus
–
Strain gauge, Dial gauge, simply supported beam, weights, measuring
instruments (scale, vernier scale, digital strain meter), loading system.
•
Purpose
–
To determine the gauge factor of resistance strain gauge
–
To determine the Young’s Modulus of the given material (beam).
•
Working principle
–
External load applied on material produces strain.
–
Strain gauge with the help of strain-meter measures the strain developed in
beams.
–
Gauge factor is obtained with the help of strain meter and dial gauge reading
–
Young modulus is obtained with the help of beam parameters and its deflection

18. Expt3: Gauge factor of resistance strain Gauge
•
Known parameters (after measurement)
–
Width of section (b), depth of section (d), Span of beam(L),
–
Deflection in dial gauge ( )
–
Moment of inertia
•
Young modulus of material
•
Strain in beam
=section modulus
•
3
12
bd
I =
pa
Ez
ε =
max∂
( )2 2
max
3 4
24
pa
E l a
I
= −
∂
R
K
Rε
∆
=
R
R
∆
2
6
bd
z =

19. Expt3: Gauge factor of resistance strain Gauge
•
Procedure
–
Prepare the experimental set up as shown in figure
–
Measure the all parameters
• Beam- width, depth, point of load, span length,
–
Strain and dial gauges should be at middle of span
–
Put load on load hooks (same on both)
–
Note dial and strain meter reading ( and )
–
Repeat the test for different set of loading (increasing
and decreasing)
R
R
∆
max∂
( )2 2
max
3 4
24
pa
E l a
I
= −
∂
R
K
Rε
∆
=
pa
Ez
ε =
R
R
∆

20. Expt3: Gauge factor of resistance strain Gauge
Sl
No
Load
(p)
Distance
(mm)
Loading unloading Young
modulus
Strain Gauge
factor
(K)Dial
gauge
Strain
meter
Dial
gauge
Strain
meter
1
2
3
4
5
6
7
8
Average
R
R
∆R
R
∆
max∂
max∂
ε
E

21. End of experiment 3

22. Expt 4: Calibration of Accelerometer

23. Expt 4: Calibration of Accelerometer
•
Apparatus
–
Accelerometer, Data acquisition, Arrangement for circular movement
•
Purpose of Accelerometer
–
To measure the acceleration
•
Type of accelerometer
–
Potentiometric
–
Piezoelectric
–
Resistive type
–
Capacitive type
–
Vibrating quartz
•
Working

24. Expt 4: Calibration of Accelerometer
•
Procedure
–
Connect accelerometer on circular mount
–
Connect accelerometer wire to data acquisition system
–
Set data acquisition system for the range of accelerometer
–
Keep accelerometer arm perfectly vertical and set data acquisition
meter to zero or to take the displayed reading as reference
–
Move accelerometer arm clock wise in step of 5 degree and note the
reading in data acquisition system.
–
Repeat the above step for anti clock wise movement of accelerometer
arm

25. Expt 4: Calibration of Accelerometer
Angle in degree Measured voltage
Clock wise Anti clock wise Average
0
5
10
15
20
25
30
|
|
|
90

26. End of experiment 4

27. Expt 5: Calibration of pressure transducer

28. Expt 5: Calibration of pressure transducer

29. Expt 5: Calibration of pressure transducer

30. Expt 5: Calibration of pressure Transducer
•
Apparatus
–
Pressure transducer, dead weight calibration, Pressure gauge
•
Purpose
–
To calibrate the pressure transducer for measuring pressure in field
environment
•
Working principle
–
Pressure is an expression of force per unit area of application
–
Pressure transducer generates the signal (electrical) as a function of
pressure imposed
–
For calibration a known pressure is applied on pressure transducer with
the help of hydraulic fluid.

31. Expt 5: Calibration of pressure transducer
•
Procedure
–
Switch on the data acquisition system and fix the range according to pressure transducer as
shown in figure
–
Centre column is fitted with dead weight and right column is fitted with pressure transducer
–
Open the cock on the left of calibrator and rotate the piston handle to counter clock-wise to
allow the oil to enter in chamber
–
Close the cock
–
Rotate the piston handle slowly in clockwise direction to pressurize the two columns.
Centre column will lift and will show red mark
–
Red mark ensures that pressure in fluid is exactly same as pressure applied in centre
column.
–
Take the reading of data acquisition system for applied pressure on centre column.
–
Repeat the procedure for different pressure applied at centre column.

32. Expt 5: Calibration of pressure transducer
Sl No Pressure (bar) Voltage
1
2
3
4
5
6
7
8
9
10
11
12
Plot pressure Vs voltage and get the slope (bar/volt)

33. End of experiment 5

34. Expt 6: Calibration of Inclinometer

35. Expt 6: Calibration of Inclinometer

36. Expt 6: Calibration of Inclinometer
•
Apparatus
–
Inclinometer, DC supplier, Multi-meter
•
Purpose of Inclinometer
–
To measure the angle of inclination
•
Type of inclinometer
–
Potentiometric
–
LVDT
–
Piezoelectric
•
Working
–
Consists of spring mass system attached with ferromagnetic substance
which produces current

37. Expt 6: Calibration of Inclinometer
•
Procedure
–
Connect inclinometer on circular mount
–
Connect inclinometer wire to DC current supplier and multi-meter
–
Keep inclinometer arm perfectly vertical and take the displayed
reading as reference value
–
Move inclinometer arm clock wise in step of 10 degree up to (80
degree) and note the reading from multi-meter.
–
repeat the step in anti clock wise direction and go up to -80 degree
and come back to 0 degree (vertical arm)
( )
Position Angle(degree)
0.025
outV RF inVolt−
=
Manufacturer calibration coefficient (volt/degree)

38. Expt 6: Calibration of Inclinometer
Angle in degree Measured voltage
Clock wise Anti clock wise Average
-80
-70
-60
|
0 Reference value
(RF)
10
20
30
|
|
80Plot volt Vs angle to get calibration coef. (volt/degree)

39. Expt 6: Calibration of Inclinometer

40. End of experiment 6

41. Expt 7: Calibration of Load cell

42. Expt 7: Calibration of Load cell

43. Expt 7: Calibration of Load cell
Canister load cell S-type load cell
Cantilever type load cell Miniature type load cell
Piezoresistive load
cell

44. Expt 7: Calibration of Load cell
•
Apparatus
–
Load cell, Strain meter, Loading pan, Loads
•
Purpose of load cell
–
To measure the time varying load
•
Type of load cell
–
Cantilever type
–
Canister type
–
Miniature type
–
Piezoresistive type
•
Working
–
Consists of strain gauge with bending arrangement

45. Expt 7: Calibration of Load cell
•
Procedure
–
Fix the one hanging end of cantilever type load cell to rigid body
–
Connect the load cell to strain meter
–
Tune the strain meter display to zero for no load
–
At loading end of load cell apply the load with the help of load pan
and note down the strain meter reading
–
Increase the load and note down the strain meter reading
–
Repeat the steps for increasing load and then for decreasing load

46. Expt 7: Calibration of Load cell
SL no Load (gram) Measured voltage
Loading Unloading Average
1
2
3
4
5
6
7
8
9
10
Plot load Vs voltage to get the slope i.e. calibration coef. (gram/volt)

47. End of experiment 7

48. Expt 8: Use of data acquisition system, signal
generator

49. Expt 8: Use of data acquisition system, signal
generator

50. Expt 8: Use of data acquisition system, signal
generator

51. Expt 8: Use of data acquisition system, signal
generator
•
Apparatus
–
Signal generator, Data acquisition card, Computer with software
•
Purpose of experiment
–
To acquire the data from signal generator in digital form
•
Working
–
Signal generator is a electronic device which generates continuous
analog signal at different frequency and amplitude.
–
Signal generator can generate different type of signal (sin, cosine,
trapezoidal etc)
–
Data acquisition card (HBM spider8) acquires the continuous analog
signal and transform that into digital form.
–
With the help of software acquired digital signal is stored on spread
sheet.

52. Expt 8: Use of data acquisition system, signal
generator
•
Procedure
–
Connect signal generator out put to spider8 (data acquisition card)
first port (zeroth port)
–
Connect the output of spider8 to the computer
–
Switch on the signal generator and software in computer
–
Tuned the signal generator for sin wave and specified frequency and
amplitude
–
Click on start button of software to start acquiring the data
–
Acquire the data for at least 10 seconds then stop and save the data
on spread sheet
–
Change the frequency in signal generator and repeat the step for data
acquisition
–
Plot the acquired data along the time and compare with

53. End of experiment 8