NATIONAL INSTITUTE OF TECHNOLOGY TRICHY

DEPARTMENT OF INSTRUMENTATION AND CONTROL ENGINEERING

IC 212 SENSORS AND TRANSDUCERS LABORATORY

EXPERIMENT - DOCUMENTATION

SECOND YEAR- B.TECH

DEPARTMENT OF INSTRUMENTATION AND CONTROL ENGINEERING

SENSORS AND TRANSDUCER LAB

SI.NO LIST OF EXPERIMENTS

1

Measurement of strain using strain gauges

2

Characteristics of temperature sensors

3

Study Of Ac And Dc Characteristics Of LVDT

4 Measurement of Natural frequency and damping ratio of the given

system

5

Loading effects of Potentiometer and Characteristics of Optocoupler

6

Level Measurement using proximity sensors

7 Effect of Modifying and Interfering input for the given measurement

system

8

Characteristics of Hall effect sensor

1.MEASUREMENT OF STRAIN USING STRAIN GAUGES

AIM:

To measure the strain in a cantilever beam setup using half and full bridge

configurations of strain gauge using cantilever beam setup.

APPARATUS REQUIRED:

S.No Components/Apparatus Specification or Range Quantity

1.

2.

3.

4.

5.

Cantilever beam setup

with strain gauge in

Resistors

Weights

RPS

Breadboard

EXPERIMENTAL SETUP:

Half Bridge Configuration

SG1 Force/load

SG2 Cantilever beam

Full Bridge Configuration

CIRCUIT DIAGRAM 1 &2 :

Half Bridge Configuration and Full Bridge Configuration

Circuit diagram1: Half bridge configuration

Circuit diagram2: Full bridge configuration

FORMULA (used for the experiment)

DIMENSIONS OF CANTILEVER BEAM: (Write the values of the quantities with units)

Youngs Modulus (E) =

Width of the beam (b) =

Length of the beam (l) =

Thickness of the beam (h) =

Bridge Excitation voltage (Ev) =

Gauge factor strain gauge (GF) =

THEORITICAL CALCULATIONS:

Ixx = b h3 / 12 ; Ixx - Moment of Inertia in mm

4

d = P l3 / 3E Ixx; d- Deflection of the beam,

P- Rated load of the beam in gm

= M Y/ Ixx; M Bending moment = g l

Y = h/2.

- Stress in kg/mm2

= / E; - Strain

VO = Ev GF For Half Bridge configuration

VO = Ev GF / 4 For Quarter bridge configuration

TABULATION 1:

Half Bridge Configuration

Load

(gms)

Bridge

Volt(v)

Deflection

d(mm)

Stress

x 10-6

Strain

x 10-5

Eth(mV) H(I) N

x10-6

S/N

x 10-

6

N(I)

Increasing Decreasing

TABULATION 2:

Full Bridge Configuration

Load

(gms)

Bridge

Volt(v)

Deflection

d(mm)

Stress

x 10-6

Strain

x 10-5

Eth(mV) H(I) N

x10-6

S/N

x 10-

6

N(I)

Increasing Decreasing

Procedure:

1. The circuit connections are made as per the circuit diagram 1 and 2. .

2. Note corresponding outputs while bridge (half/Full) is loaded in multiples of 100gms till

1000gms.

3. Do the same while unloading the bridge(half/Full).

4. Plot the graph for load Vs bridge output, hysteresis and non-linearity

Result:

Inference about the experiment :

2.CHARACTERISTICS OF TEMPERATURE SENSORS

AIM:

To study the characteristics of the given Resistance temperature detector (RTD),

Thermocouple and Thermistor.

APPARATUS REQUIRED:

S.No Components/Apparatus Specification or Range Quantity

1.

2.

3.

4.

5.

RTD

Thermocouple

Thermistor

Thermal calibrator

Digital Multimeter

EXPERIMENTAL SETUP:

TABULATION: 1 VARIATION OF RESISTANCE OF RTD WITH TEMPERATURE

S.NO TEMPERATURE(DEGREE CELSIUS)

RESISTANCE(KILO OHM)

TABULATION: 2 VARIATION OF OUTPUT VOLTAGE OF THE THERMOCOUPL WITH

TEMPERATURE

S.NO TEMPERATURE(DEGREE CELSIUS)

THERMO EMF(MILLIVOLT)

TABULATION: 3 VARIATION OF RESISTANCE OF THERMISTOR WITH TEMPERATURE

S.NO TEMPERATURE(DEGREE CELSIUS)

RESISTANCE(KILO OHM)

PROCEDURE:

1. Experimental setup is as shown in figure. Connect the thermal calibrator to the power

supply.

2. Insert the RTD, Thermocouple and thermistor into the thermal calibrator and set the

range of temperature from room temperature to _________ degree

3. Connect a multimeter to the two leads of RTD, Thermocouple and the thermistor and

measure the output resistances and voltage for each 10 degree rise in temperature to

maximum temperature.

4. Repeat the same procedure in the reverse order

5. Tabulate readings and plot graph to study characteristics

i)Voltage Temperature for thermocouple

ii)Resistance-Temperature for RTD and thermistor

7.Set the temperature of calibrator to room temperature and allow it to cool down.

RESULT:

Inference about the experiment :

3.STUDY OF AC AND DC CHARACTERISTICS OF LVDT

AIM

To study the AC and DC characteristics of the given LVDT

APPARATUS REQUIRED:

S.No Components/Apparatus Specification or Range Quantity

1.

2.

3.

4.

5.

6.

7.

LVDT

DSO

Function generator

Resistor

Capacitor

Diodes

Multimeter

CIRCUIT DIAGRAM 1 : AC CHARACTERISTICS

CIRCUIT DIAGRAM 2 : DC CHARACTERISTICS

Input Excitation voltage:

Input Excitation Frequency:

TABULATION 1 :

S.No Displacement (mm) Ac voltage (mV) Dc voltage(mV)

PROCEDURE:

a) To study AC Characteristics:

1. The connections are made as shown in circuit diagram 1. The core is

kept at one extreme end and the output voltage is noted at this point.

2. Next the core is moved slowly to the other end and

displacement is measured using screw gauge and the corresponding

voltages are noted.

3. The point where the output voltage is zero is the null point.

4. Draw the graph between displacement Vs AC output voltage. Find the

null point of the given LVDT and the range of displacement.

b) To study DC Characteristics:

1. The connections are made as shown in the circuit diagram 2.

2.Next the core is moved slowly to the other end and the displacement

is measured using screw gauge. The value of the output voltage was

taken after a particular displacement was moved.

3. The point where the output voltage is zero is the null point. The

readings were plotted on a graph sheet.

RESULT:

Inference from the experiment:

4.EFFECTS OF INTEREFERING AND MODIFYING INPUTS FOR THE

GIVEN MEASUREMENT SYSTEM

AIM:

To study the effect of interfering and modifying inputs on a system of strain

gauge mounted on a cantilever beam using quarter bridge configuration.

APPARATUS REQUIRED:

Sl.No Name of the

component/equipment Specifications(Range/Value) Quantity

1 Strain gauge mounted on

cantilever beam(quarter

bridge configuration)

2 DC regulated power

supply

3 Weights

4 IC temperature measuring

sensor

5 Heating strip-bimetallic

strip

6 Breadboard

7 Resistors

8 Digital multimeter

TABULATION:

a) The effect of modifying input

Sl.No Load(g) Vs =

Output voltage

Vo(mv)

Vs =

Output voltage

Vo(mv)

Vs =

Output voltage

Vo(mv)

b) The effect of interfering input

S.No Load(g) Temperature =

Output voltage

Vo(mv)

Temperature =

Output voltage

Vo(mv)

Temperature =

Output voltage

Vo(mv)

EXPERIMENTAL SETUP:

CIRCUIT DIAGRAM:

PROCEDURE:

a) Modifying input

1. Connect the circuit as shown in figure. Do not give any supply to the heating

element or to the IC temperature sensor LM 35.

2. Keep the supply voltage constant at 4V and note the output voltage when there

is no load.

3. Keep the weights on the cantilever beam and note the output voltage for

different values of weights using a multimeter.

4. Repeat steps 2 and 3 for different values of supply voltages.

5. Plot a graph between the output voltage and the load on the cantilever beam

and note down the sensitivity of the three different readings.

b) Interfering input

1. Make the circuit as shown in figure. For the cantilever beam setup use the

other figure. Give the heating element a 220V.single phase power supply and IC

temperature sensor (LM 35) a supply voltage of 5V.

2. Keep the supply voltage constant at 5V.

3. Allow the strain gauge setup to be heated and note down the temperature with

LM 35 of sensitivity 10 mV/degree Celsius.

4. At a temperature different from room temperature note down the output voltage

at no load conditions and also for different weights.

5. Repeat step 4 for another temperature.

6.Plot the graph for the variation of output voltage with load and note the effect of

interfering input.

RESULT:

Inference from the experiment

5.CHARACTERISTICS OF PROXIMITY SENSORS

AIM

To obtain the characteristics of proximity sensor.

APPARATUS REQUIRED

Sl.No Equipments required Specification Quantity

1 Proximity sensors

2 Regulated power supply

3 Connecting wires

4 Voltmeter

5 Ammeter

6 Resistor

TABULATION:

Sl.No. Distance(cm) Output

current(mA)

Output

voltage(mV)

EXPERIMENTAL SETUP:

PROCEDURE:

a) Current output proximity sensor (UP-1000 PVPS 24(M))

1. The sensor is excited with a 24 V DC power supply as shown in figure.

2. A resistance of 470 is connected across the green and white wires from the

sensor. An ammeter is connected in series with the loop to get the output

sensor.

3. A resistance of 180 is connected across yellow and white wires from the

sensor.

4. The target is placed at ______ cm distance from the sensor and moved away in

steps of 5cm at a time and the corresponding output current is noted.

5. Plot the characteristics of current Vs distance,

b) Voltage output proximity sensor (UP 2000 PVPS 24 1S(K)

1. The sensor is excited with a 24 V DC supply.

2. The output voltage is taken across the green and white wires, assuming white

to be grounded.

3. The effective resistance of 180k is connected between the yellow and white

wires as shown in figure3.the target is placed at----------- cm from sensor and

moved away in steps of------cm each at a time. The output voltage

corresponding to each step is noted.

4. Plot the characteristics of output voltage Vs distance.

RESULT:

Inference from the experiment:

6.MEASUREMENT OF NATURAL FREQUENCY AND DAMPING RATIO

OF THE GIVEN SECOND ORDER SYSTEM

6.1.MEASUREMENT OF DAMPING RATIO

AIM:

To determine the damping ratio of second order system experimentally using

logarithmic decrement method.

APPARATUS REQUIRED:

Sl.No Equipment Required Specifications Quantity

1 Piezo-laminated Cantilever beam

2 Digital storage oscilloscope

3 Connecting probes

TABULATION:

Sl.No No:of cycles(r) iA (V) riA (V)

ri

i

A

A

rln

2

1

EXPERIMENTAL SETUP:

PROCEDURE:

1. The experiment setup is shown above.

2. An impulse input is applied to the free end of the cantilever beam by tapping it

3. This causes the cantilever beam to vibrate and hence the PZT gives an electrical

output observable to the DSO.

4. The output is a continuous exponentially decaying sinusoidal wave. The

amplitudes of the i th and the i+r th waveforms are noted down where r is the

number of cycles between them.

5. Substitute the values of Ai, A(i+r) in the formula to get the damping ratio .

6. By varying the number of cycles considered during different times of application

of impulse input, several readings are taken and their mean is noted down as the

damping ratio.

6.2. MEASUREMENT OF NATURAL FREQUENCY

AIM:

To measure the natural frequency of a Piezo-laminated cantilever beam

APPARATUS REQUIRED:

Sl.No Equipments Specification Quantity

1 Piezo-laminated

cantilever beam

2 Function generator

3 DSO

4 Resistors

5 Capacitors

6 Opamp

EXPERIMENTAL SETUP:

Cantilever beam

Piezoelectric crystal

FUNCTION

GENERATO

R

CHARGE

AMPLIFIER

DSO

CHARGE AMPLIFIER CIRCUIT

C=0.01F

FROM PZT

OSCILL0SCOPE

+

TABULATION:

Sl.No Frequency(Hz) Output voltage

without charge

amplifier,Vo(volts)

Output voltage with

chargeamplifier,Vo(volts)

IC741

PROCEDURE:

i) Without charge amplifier

a. Connect the actuator to the output from function generator.

b. The output from the piezo-electric sensor is fed directly to oscilloscope.

c. Vary the frequency of the input sinusoid in the range (0-60)Hz and observe the

output with aid of oscilloscope and note down the readings.

d. Observe for the resonance peak at which very high output are observed.

ii) With charge amplifier

a. Connect the circuit as shown in figure.

b. Cary the frequency of the input signal in the range (0-60)Hz.

c. Repeat steps c and d of without charge amplifier.

RESULT:

Inference from the experiment

7.LOADING EFFECTS OF POTENTIOMETER AND

CHARACTERISTICS OF OPTOCOUPLER

7.1.LOADING EFFECTS OF POTENTIOMETER

AIM:

1. To study the loading effect of a rotary potentiometer.

2. To study the characteristics of optocoupler

APPARATUS REQUIRED:

Loading effect of potentiometer

Sl.No Equipments Required Specifications Quantity

1 Rotary potentiometer

2 Analog Voltmeter of different

ranges

3 Regulated DC power supply

4 Multimeter

5 Connecting wires

TABULATION:

Sl.No:

max

Voltmeter Rm=

Range=

Voltmeter Rm=

Range=

Vo Vi

Vo Nonlinerity Vo

Vi

Vo Nonlinerity

CIRCUIT DIAGRAM:

PROCEDURE:

1. The experimental setup is made as per in figure

2. The input ports given on the potentiometer is connected to 5V DC

3. After all connections are made switch on the DC power supply.

4. Using the voltmeter (0-5V), measure the output voltage for different angles of

rotation.

5. Measure the output voltage for different angles using 0-10V voltmeter.

6. Draw a graph between Vo/Vi and max

and also the graph representing the

nonlinearity

7.2.CHARACTERISTICS OF OPTOCOUPLER

AIM:

To study the characteristics of a

i)photodiode

ii)phototransistor

APPARATUS REQUIRED:

Sl.No Equipments Required Specifications Quantity

1 Photodiode

2 LED

3 Ammeter

4 Rheostat

5 Resistance

6 dc supply

7 npn transistor

8 IC-chip (MCT-2E).

Circuit diagram

i) Photo diode RHEOSTAT

+ _ (0-20)mA +5v

VIN ID55

5V

1m

-5V

Vout

ii) Photo Transistor

npn transistor Vout

A

TABULATION 1:

Sl.No I/p current(mA) O/p voltage(V)

TABULATION 2:

PROCEDURE:

1. The circuit is shown as in the figure.

2. The resistance is varied using a pot so that input current is varied.The output

current and output voltage is noted.

3. The reading is tabulated and graphs are drawn.

4. The same procedure is repeated for circuit 1 and 2.

RESULT:

Inference from the experiment

Sl.No I/p current(mA) O/p current(mA) Voltage(V)

8.CHARACTERISTICS OF HALL EFFECT SENSORS

AIM:

To study the characteristics of Hall effect sensor.

APPARATUS REQUIRED:

Sl.No Equipments Required Specifications Quantity

1 Hall Probe

2 Digital Hall effect set, Model

DHE-22

3 Electromagnet,Model-EMU-

50/EMU-75

4 Constant current power supply

5 Digital Gauss Meter

Sample for study Hall Effect

TABULATION:

1. Constant.Gauss.

FORWARDED REVERSE

I(mA) V(mV) I(mA) V(mV)

2. Current ConstantmA

Current Mill volt

PROCEDURE

1. Connect the widthwise contact f the Hall probe to the terminals marked

Voltage and Lengthwise contact to the terminals marked Current.

2. Switch On the hall effect set-up and adjust the Current (say few mA).

3. Switch over the display to Voltage side.

4. Place the probe in the magnetic field as shown in the figure and switch ON the

electromagnet power supply and adjust the current to any desired value. Rotate the

hall probe till it become perpendicular to the magnetic field.

5. Measure hall Voltage for both direction of the current and the magnetic field.

6. Measure the hall voltage as a function of the current. Keeping the magnetic field

constant plot a graph.

7. Measure the hall voltage as a function of the Magnetic field. Keeping a suitable

value of current as constant plot the graph.

8. Measure the magnetic field by the Gauss meter.

RESULT:

Inference from the experiment