transducer and instrumentation lab manual

MtE-317 (L)

Lab Instructor: Engr. Anam Abid

Institute of Mechatronics Engineering

5th Semester

Transducers and Instrumentation Lab Manual

Transducers and Instrumentation Lab Page 1

Course code: MtE-317 (L)

Transducers and Instrumentation Lab

Lab Instructor: Engr. Anam Abid

No. Title Grade Data

1 Laboratory Introduction

2 Light Transducer: Phototransistor

3 Temperature Transducer: RTD, Thermocouples

4 Position Transducer: Linear Potentiometer

5 Position Transducer: LVDT

6 Speed Transducer: Tacho- Generator

7 Speed Transducer: Photoelectric RPM meter

8 Force Transducer: Extensometer/ Strain Gauge

9 Level Transducer

10 Proximity Transducer


List of Experiments

1. Explore different types of transducers in the laboratory.

Objectives:

a. Visit Instrumentation laboratory

b. Explore different transducer modules available in the lab

c. List and classify transducers on the basis of classification schemes studied in

theory class

2. Plot the characteristic curve of phototransistor

Objectives:

a. Explore the working principle of phototransistor

b. Study signal conditioning method of phototransistor

c. Plot and investigate the characteristic curve of phototransistor

3. Plot the characteristic curve of RTD and Thermocouple

Objectives:

a. Explore the working principle of RTD and Thermocouple

b. Study signal conditioning circuits of RTD and Thermocouple

c. Plot and investigate the characteristic curves of RTD and Thermocouple

4. Perform Calibration of Position Transducer signal conditioner and plot

Displacement/Voltage characteristic curve

Objectives:

a. Explore the working principle of position transducer

b. Calibrate the signal conditioner

c. Plot and investigate the characteristic curve of position transducer

5. Perform Calibration of LVDT Transducer signal conditioner and plot

Displacement/Voltage characteristic curve

Objectives:

a. Explore the working principle of LVDT transducer

b. Calibrate the signal conditioner (0mm → 0V; 25mm → 8V)


6. Plot the characteristic curve of Tacho-generator

Objectives:

a. Explore the working principle of Tacho-generator Transducer

b. Study the signal conditioner for Tacho-generator

c. Plot and investigate the characteristic curve of Tacho-generator


7. Analysis of Photoelectric Speed Transducer

Objectives:

a. Explore the working principle of Photoelectric Speed Transducer

b. Analyze the signals supplied by Transducer and its signal conditioner

c. Investigate the accuracy of signals supplied by Transducer and its signal

conditioner

8. Perform Force transducer calibration and plot output voltage/force curve

Objectives:

a. Explore the working principle of Force transducer

b. Calibrate the signal conditioner for Force transducer

c. Plot and investigate the characteristic curve of Force transducer

9. Detecting a Level with single threshold.

Objectives:

a. Explore the working principle of Level transducer

b. Study the signal conditioning method for Level transducer

c. Detect a Level with Threshold detector

10. Perform Proximity transducer calibration and plot distance range/ voltage characteristic

curve

Objectives:

a. Explore the working principle of Proximity transducer

b. Calibrate the signal conditioner for Proximity transducer

c. Plot characteristic curve of distance range and voltage


Experiment No. 1

Title: Explore different types of transducers in the laboratory

Objectives:

a. Visit Instrumentation laboratory

b. Explore different transducer modules available in the lab

c. List and classify transducers on the basis of classification schemes studied in theory class

Theory:

Transducer:

The term „transducer‟ signifies a device which absorb energy from one system and supplies this

energy, generally in another form (such as electrical variable), to a second system. Usually,

transducer output can be a voltage, a current, a resistance, and so on. Generally, transducers are

used in instrumentation systems to measure different physical quantities e.g. temperature,

distance, speed, force, strain, vibration, pressure, flow etc.

Classification of Transducers:

There are many criteria on the basis of which transducers can be classified, as given in the

following.

1. Measurand physical quantity

2. Energy consideration

3. Nature of signal

4. Mode of Operation

5. Contact with measurand medium

Transducer classification schemes are briefly discussed here.

1. Measurand Physical Quantity

On the basis of measurand physical quantity and application, there can be several types of

transducers such as

Temperature transducers

Displacement transducers

Motion transducers

o Speed transducer

o Velocity transducer

o Acceleration transducer

Force/ Torque transducer


Strain transducer

Vibration transducer

Sound transducer

Flow rate transducer

Flow transducer

Level transducer

Pressure transducer

Light transducer

Humidity transducer

2. Energy Consideration

On the basis of energy consideration transducers can be classified as passive or active

transducers. A component whose output energy is supplied entirely or almost entirely by its input

signal is commonly called a passive transducer. An active transducer, however, has an auxiliary

source of power, which supplies a major part of the output power, while the input signal supplies

only an insignificant portion.

3. Nature of signal

By turning attention to the nature of signals that represent the information, transducers can be

classified into analog and digital types. For analog signal, the precise value of the quantity

(voltage, rotation angle etc.) carrying the information is significant. However, digital signals are

basically of a binary (on/off) nature in the form of dc pulses.

4. Mode of Operation

Another useful classification separates devices by their operation on null and deflection

principle. In a deflection-type device, the measurand quantity produces some effect that

engenders a similar but opposing effect in some part of the instrument. This opposing effect is

closely related to some mechanical displacement or deflection. This opposing effect increases

until a balance is achieved, at which point amount of „deflection‟ represents the value of

measurand quantity. In contrast, a null-type device attempts to maintain deflection at zero by

suitable application of an effect opposing that generated by the measurand quantity. The accurate

knowledge of the magnitude of the opposing effect that keeps deflection zero (ideally)

determines the value of measurand quantity.

5. Contact with measurand medium

On the basis of contact of the transducer with measurand medium, we have contact and

contactless/ proximity transducers. If the transducer is in direct physical contact with measurand

medium, it falls in the former category. If transducer element lies in the vicinity of measurand

medium but not in direct contact, it falls in contactless/proximity transducer category.


Classification of Transducer Modules

Transducer

Module

Classification Criteria

Measurand

Quantity

Energy

Consideration

Nature of

Signal

Mode of

Operation

Contact with

Medium


Experiment No. 2

Title: Plot the characteristic curve of Phototransistor

Objectives:

a. Explore the working principle of phototransistor

b. Study signal conditioning method of phototransistor

c. Plot and investigate the characteristic curve of phototransistor

Theory:

A phototransistor is a device that converts light energy into electric energy. A phototransistor is

made of a bipolar semiconductor and focuses the energy that is passed through it. Photons (light

particles) activate phototransistors and are used in virtually all electronic devices that depend on

light in some way. Although ordinary transistors exhibit the photosensitive effects if they are

exposed to light, the structure of the phototransistor is specifically optimized for photo

applications. The photo transistor has much larger base and collector areas than would be used

for a normal transistor.

Phototransistors are generally encased in an opaque or clear container in order to enhance light

as it travels through it and allow the light to reach the phototransistor‟s sensitive parts. The light

enters the base region of the phototransistor where it causes electron-hole pairs to be generated.

This mainly occurs in the reverse biased base-collector junction. The hole-electron pairs move

under the influence of the electric field and provide the base current, causing electrons to be

injected into the emitter.

Photo transistors are operated in their active region, although the base connection is left open

circuit or disconnected because it is not required. The base of the photo transistor would only be

used to bias the transistor so that additional collector current was flowing and this would mask

any current flowing as a result of the photo-action. For operation the bias conditions are quite

simple. The collector of an n-p-n transistor is made positive with respect to the emitter or

negative for a p-n-p transistor.

Figure 1. Phototransistor


Module Connections:

Figure 1

Figure 2

Procedure:

1. Make the module connections as shown in the figure 1.

2. Connect module G13 to unit TY13/EV.

3. Set the switch of the Phototransistor conditioner block to the position A.

4. Set the multimeter for current measurements and connect it between terminal 23 and

ground.

5. Connect module G13 to all necessary supplies.

6. Set the lamp to the maximum distance with the slide.

7. With the Set-point positioned at the maximum value which corresponds to a light of 370

lux, set the PID controller proportional knob to the maximum.


8. Move the lamp near the light transducer with the slide and in correspondence to the

divisions shown on the panel, read the current value indicated by the multimeter and

report them in the table.

9. Plot a graph with illumination on x-axis and current on y-axis and draw the points

detected.

10. The characteristic curve of the transducer is obtained by joining these points.

11. Remove the multimeter terminal 23 and ground, take the switch to B and insert the

multimeter selected as dc voltmeter between terminal 28 and ground (figure 2).

12. Report all the last measurements; in this case measure the response of the transducer

together with signal conditioner.

13. Plot a graph with illumination on x-axis and voltage on y-axis and draw the points

detected.

14. The characteristic curve of the transducer together with signal conditioner is obtained by

joining these points.

Observations:

No. Lux Ampere Volt


Experiment No. 3

Title: Plot the characteristic curves of RTD and Thermocouple

Objectives:

a. Explore the working principle of RTD and Thermocouple

b. Study signal conditioning circuits of RTD and Thermocouple

c. Plot and investigate the characteristic curves of RTD and Thermocouple

Theory:

Resistive Temperature Detectors (RTDs):

RTDs are made up of metal wire or fiber material that responds to temperature change by

changing resistance. Platinum, nickel, and tungsten are mostly used that have high resistivity,

good temperature coefficient of resistance, good tensile strength and chemical inertness with

packaging and insulation materials. The change in resistance can be determined using a bridge

circuit. RTDs are generally more accurate than thermocouples, but are less rugged and cannot be

used at high temperatures.

Thermocouples:

Thermocouple is the most popular type of sensor. It is based on the principle that two wires made

of dissimilar materials connected at either end will generate a potential between the two ends that

is the function of materials and temperature difference between two ends. Base metal

thermocouples are useful for measurement of temperatures under 1000 degree Celsius. This class

includes iron/constantan (Type J), Chromel/Alumed (Type K) and number of others. Nobel metal

thermocouples are useful to about 2000 degree Celsius. This class includes tungsten-rhenium

alloy thermocouples and others. The potential generated is in millivolts and is a nonlinear

function of temperature. In practice, one end is placed near the material to be measured

(measuring junction) and the other end is connected to the instrument. Inside instrument is a

reference junction whose temperature is maintained using appropriate heat insulation.


Procedure:

1. Connect the temperature module with all necessary supplies.

2. Connect the TY34 unit to the module.

3. Connect the probes for RTD and Thermocouple transducers in the TY34 unit.

4. Connect set point to the minimum and connect terminal 2 to terminal 11.

5. Turn on the power supply.

6. Note the steady-state temperature using the mercury thermometer and note the

corresponding output of both signal conditioners.

7. Repeat all measurements for increasing values of set points.

8. Tabulate all the values.

9. Plot all measurements on a graph.

Observations:

No. Set Point RTD (output) Thermocouple (output)


Experiment No. 4

Title: Perform calibration of Position Transducer signal conditioner and plot displacement/

voltage characteristic curve

Objectives:

a. Explore the working principle of position transducer

b. Calibrate the signal conditioner


Theory:

A displacement transducer using variable resistance transduction principle can be manufactured

with a rotary or linear potentiometer. A potentiometer is a transducer in which a rotation or

displacement is converted into a potential difference. As shown in the figure, the displacement of

the wiper of a potentiometer causes the output potential difference obtained between one end of

the resistance and the slider. The position of the slider along the resistance element determines

the magnitude of the electrical potential. The voltage across the wiper of linear potentiometer is

measured in terms of the displacement, d, and given by the relationship

d

V EL

E is the voltage across the potentiometer, and L is the full-scale displacement of the

potentiometer.

Procedure:

1. Connect the panel sockets to ±12V and 0C to a regulated power supply.

2. Connect the digital voltmeter between the socket +Vref and ground.

3. Switch the regulated power supply on.

4. Calibrate the terminal RV1 until the digital Voltmeter goes to +8.00V (calibration of the

voltage +Vref).

5. After calibration, connect the digital voltmeter between test point 3 and ground.


6. Vary the slider distance (from the zero position) with steps of about 2 mm and observe

both the relevant reference distance on the graduated scale and the output voltage.

7. Tabulate the readings.

8. Plot readings on a graph.

Observations:

No. L (mm) Vout


Experiment No. 5

Title: Perform calibration of LVDT Transducer signal conditioner and plot displacement/

voltage characteristic curve

Objectives:

a. Explore the working principle of LVDT transducer

b. Calibrate the signal conditioner (0mm → 0V; 25mm → 8V)


Theory:

Linear Variable Differential Transformers (LVDTs) are the most widely used transducers. They

are used to measure displacement directly as a sensing element in a number of situations

involving motion. LVDTs can resolve very small displacements. Their high resolution, high

accuracy, and good stability make them an ideal device for applications involving short

displacement measurements.

LVDTs consist of one primary winding, P1, and two secondary windings, S1 and S2. Each is

wound on a cylindrical former with rod-shaped magnetic cores positioned centrally inside the

coil assemblies. This provides a dedicated path for the magnetic flux linking the coils. An

oscillating excitation voltage is applied to the primary coil. The current through the primary

creates voltages in secondary windings. The ferromagnetic core concentrates the magnetic field.

If the core is closer to one of the secondary coils, the voltage in that coil will be higher.

Let the output of the secondary winding S1 be Es1 and that of S2 be Es2. When the core is at its

normal null position, equal voltages are induced in each coil. When these two outputs are

connected in phase opposition, as shown in Figure, the magnitude of the resultant voltage will be

zero. This is known as the null position, and the output Es1 will be equal to Es2. As the moving

core is displaced, the mutual inductance between the fixed coils changes. The LVDT outputs a

bipolar voltage proportional to displacement. The output voltage is positive and gives no

indication of the direction in which the core has been moved. Proper signal conditioners can be

designed to give indication of the direction.

Figure Schematic of Linear Variable Differential Transformer (LVDT)


Procedure:

1. Connect the panel sockets to ±12V and 0C to a regulated power supply.

2. Connect the digital voltmeter between the socket +8V and ground.

3. Switch the regulated power supply on.

4. Adjust RV1 to obtain +8.00V at the terminal +Vref, check that a voltage of -8V is

generated at the terminal –Vref.

5. Check that a triangular signal (Amp: 4 Vpp, frequency 2.5 kHz) is generated at terminal

17.

6. Set the LVDT slider completely in position right and left respectively; adjust RV3 to

generate a sine wave of 1 Vpp at the terminal 4.

7. Connect the channel A of the oscilloscope to the terminal 4 and channel B to the terminal

5, and adjust RV4 to obtain two signals exactly in phase when LVDT slider is completely

at right, or phase shifted by 180 degrees if the slider is completely at left.

8. Check that the rectified signal at the terminal 6 is negative, when the slider is to the left

and positive when the slider is at the right.

9. Set the LVDT slider at 0mm; adjust RV5 to obtain an output voltage of 0V.

10. Set the LVDT slider at 25mm; adjust RV6 to obtain an output voltage of 8V.

11. After calibration, connect the digital voltmeter between terminal 11 and ground.

12. Move the slider distance (from null position) with steps of about 2 mm and observe both

the actual position from the index on the mm scale or the gauge and read the output

voltage on digital Voltmeter.

13. Tabulate the readings.

14. Plot readings on a graph.


Observations:

No. L (mm) Vout


Experiment No. 6

Title: Plot the characteristic curve of Tacho-generator transducer

Objectives:

a. Explore the working principle of Tacho-generator Transducer

b. Study the signal conditioner for Tacho-generator

c. Plot and investigate the characteristic curve of Tacho-generator

Theory:

Tacho-generator is the most widely used speed transducer in the industry. The diagram of the

standard tacho-generator is shown in the figure. In order to understand the operation of

transducer, let‟s consider a coil rotating with angular speed rotation (w) in the magnetic field of a

U-type magnet. This coil is under the influence of magnetic flux according to the following

relation:

max cos( )wt

According to the law of electromagnetic induction, voltage is induced across the coil, as given by

max sin

de w wt

dt

where the maximum value of induced voltage is directly proportional to the angular speed w.


A tacho-generator consists of a stator, a rotor with N turns connected to a commutator. The

induced AC voltage in N turns is separated by brushes for a time of 2π/Nw as shown in the

figure (output voltage). Note that the magnitude and frequency of output voltage are functions of

w. To reduce the influence of ripples and obtain steady dc output proportional to angular speed,

a low-pass filtering scheme is adopted for signal conditioning of tacho-generator.

Module Connections:

Procedure:

1. Make the module connections as shown in the figure.

2. On the PID controller block, turn the proportional knob to the maximum value.

3. Connect all the necessary power lines to the module.

4. Set the multimeter for DC voltage measurement and insert it between terminal 22 and

ground.

5. Switch on the power supplies.

6. Turn the set-point knob completely clock-wise.

7. Adjust the knob of the tacho-generator conditioner block until the display of digital RPM

meter reaches 4000 RPM.

8. Adjust the set-point, set the speed values written on the table, appearing on the 4-digit

display of digital RPM meter.

9. With a multimeter, measure the voltage supplied by the tacho-generator across each of

the set values.

10. Fill the table with measured voltages.

11. Plot a graph between speed and voltage.


Observations:

Speed (RPM) Voltage

0

500

1000

1500

2000

2500

3000

3500


Experiment No. 7

Title: Analysis of Photoelectric Speed transducer

Objectives:

a. Explore the working principle of Photoelectric Speed Transducer

b. Analyze the signals supplied by Transducer and its signal conditioner

c. Investigate the accuracy of signals supplied by Transducer and its signal conditioner

Theory:

Photoelectric speed transducer generates pulse outputs with frequency as a function of speed.

Pulses are sent to the counters, followed by binary to 4-digit decimal conversion module and 7-

segement display and finally speed in r.p.m. can be read on4-digit display.

Photo electric transducers, based on masked or perforated disc system or on reflection systems,

are the most popular digital speed transducers. The disc rotation produces a shuttering effect on

the track of light source to the light sensor, so that there is a pulse corresponding to each hole or

to each section. The reflection photoelectric transducer uses a transmitter and a receiver in the

same container, instead of a projector and a receiver separately. A mask with reflecting and

opaque segments is used instead of the perforate disc. When the light emitted from the

transmitter tracks a reflection surface is sent back to the receiver. The used photodiode -

phototransistor couple operates in infrared range and provide pulse outputs with variable

frequency proportional to rotating speed. A frequency meter is used, followed by counter and 4-

digit 7segement display module.

Figure Contactless Reflective Stripe Type Tachometer


Module Connections:

Procedure:


2. Connect one probe of the oscilloscope to terminal 25 of the signal conditioner for

photoelectric transducer (Digital RPM meter).

3. Switch on the power supply.

4. Change the motor speed and observe the signal variations displayed on the oscilloscope.

5. Connect a frequency meter to terminal 25 and confront its indication (in Hz with 30

pulses per revolution) with the one supplied by the 4-digit display (in r.p.m.): if there are

differences it depends on different time bases of the two frequency meters.


Experiment No. 8

Title: Perform calibration of Force Transducer signal conditioner and plot force / voltage

characteristic curve

Objectives:

a. Explore the working principle of Force transducer

b. Calibrate the signal conditioner for Force transducer

c. Plot and investigate the characteristic curve of Force transducer

Theory:

Sensors based on resistive strain gauges, also referred to as extensometer, are extremely widely

used as force transducers. These link a percentage longitudinal expansion to the consequent

variation in resistance. The main principle is to measure the variation in the resistance of a metal

wire whose ends are fixed at the two points between which the variation in distance is to be

measured. The load cell is the form of extensometer-based force transducer most widely used in

industrial applications. It converts an applied force (weight) into a variation in the output voltage

of an extensometer bridge. In a load cell, several extensometers are generally used, and these are

connected in bridge configurations fitted to the deformable mechanical element. The strain gauge

(single or bridge) is required to excite at constant voltage. The output voltage of bridge is

normally measured by a differential amplifier for high gain component. Also, a second-order low

pass filter is fitted in order to reduce noise. Very often a trimmer is used for offset nulling (zero

calibration), and a calibration potentiometer is used to calibrate the output to its exact full-scale

value (amplification calibration).

Procedure:

1. Connect the ±12V, 0V jacks of the panel to a stabilized power module (switched off).

2. Connect the load module to the panel via the appropriate connector.

3. Connect the digital voltmeter between jack 1 and ground.

4. Switch on the stabilized power supply.

5. Calibrate trimmer RV1 until 8.0 V is shown on the digital voltmeter (calibration of the

excitation voltage).

6. Connect the digital voltmeter to the OUT output.

7. Calibrate trimmer RV2 until the digital voltmeter reads 0V (calibration of the offset of

the load cell).

8. Apply a sample load of 20 kg to the cell.

9. Calibrate trimmer RV3 until the digital voltmeter reads 8 V (calibration of the

conditioner scale).

10. After calibration, connect the digital voltmeter to the OUT output.

11. Apply known weights to the cell ( in increasing order and at intervals of 1 kg)


12. Measure the output voltages.

13. Tabulate all the measurements and plot a graph between force and voltage.

Observations:

No. F(N) = mass*g Voltage

(V)

Note: g= 9.8m/s2


Experiment No. 9

Title: Perform calibration of Level Transducer signal conditioner and plot force / voltage

characteristic curve

Objectives:

a. Explore the working principle of Level transducer

b. Study the signal conditioning method for Level transducer

c. Detect a Level with Threshold detector

Theory:

Level measurement of liquids and solids are used extensively in all types of bulk manufacturing

and storage facilities. The location of the surface may be measured for solids or liquids using

Ultrasonic, Radar (Microwave) and Capacitance methods. The most obvious method is to use a

float to determine a liquid level. The float connects via cable or tape to measuring device outside

the tank that precisely measures the length to the float. Float Types of level sensors are based on

the principle of buoyancy which is the upward force produced on a submerged object by the

displaced fluid. This force is equal to the weight of the displaced fluid. As the fluid level rises or

falls, buoyant force is transferred through mechanical linkages to your output device.

Figure Float Type Level Sensor

Also, under static conditions the level of a liquid is linked to the pressure, one can relate the level

of liquid with pressure using the following relationship

. .p L g Ms

Where p = pressure in Pascal

L = level in meter

g = acceleration due to gravity (9.81 m/s2)

Ms = specific mass of the liquid (kg. m-3

)


Consequently, it is sufficient to measure the pressure to obtain the level. Among the different

available pressure transducers, the strain gauge ones have become the mostly used. The

operating principle of these transducers is the piezosensitivity (property of material which

changes their resistance as a function of the deformation to which they are subjected).

In this system, the sensor uses the pressure of water on the column to generate an elementary

deformation on the in-built strain gauges. In strain gauges are resistors whose resistive value

depends on the deformation they are subjected. In the sensor used, the resistors are connected to

the Wheatstone‟s bridge, so that output voltage Vo varies proportionally with pressure.

Module Connections:

Procedure:


2. Starting from the minimum level, turn I1 on “LEVEL”, I2 “OFF”, I4 “ON” and close the

discharge of vertical tank.

3. Diminish the flow across the valve in series between the pump and the tank so to obtain a

more accurate measurement.

4. Measure the level at which the led TH turns on.

5. When the level is at 500mm, turn switch I4 “OFF”.

6. Slightly open the discharge of the vertical tank so that the level drops slowly.

7. Measure the level at which the led TH turns “OFF”.

8. Confront the two levels of led TH switching at increased and diminished levels.

Observations:

LED Turn ON Voltage = ……………………………………

LED Turn OFF Voltage = …………………………………….

Difference = ………………………………………………….


Experiment No. 10

Title: Perform calibration of Proximity Transducer signal conditioner and plot distance

range / voltage characteristic curve

Objectives:

a. Explore the working principle of Proximity transducer

b. Calibrate the signal conditioner for Proximity transducer (1mm → 3V, 4mm → 5V)

c. Plot characteristic curve of distance range / voltage

Theory:

Proximity sensors detect the presence of objects without physical contact. There are many types

of proximity sensors including inductive, capacitive, photoelectric, ultrasonic and radar

(microwave).

Inductive and Capacitive: Their operating principle is based on a high frequency oscillator that

creates a field in the close surroundings of the sensing surface. The presence of a metallic object

(inductive) or any material (capacitive) in the operating area causes a change of the oscillation

amplitude. The rise or fall of such oscillation is identified by a threshold circuit that changes the

output state of the sensor. The operating distance of the sensor depends on the actuator's shape

and size and is strictly linked to the nature of the material.

Photoelectric: These sensors use light sensitive elements to detect objects and are made up of an

emitter (light source) and a receiver. Three types of photoelectric sensors are available. Direct

Reflection - emitter and receiver are housed together and uses the light reflected directly off the

object for detection. Reflection with Reflector - emitter and receiver are housed together and

requires a reflector. An object is detected when it interrupts the light beam between the sensor

and reflector. Thru Beam - emitter and receiver are housed separately and detect an object when

it interrupts the light beam between the emitter and receiver.

Type Use

Inductive Detection of metallic objects

Capacitive Detection of metallic and non-metallic objects

Photoelectric Use light sensitive elements to detect objects


Procedure:

1. Connect the terminals ±12V, 0V and +5V of the panel to a regulated power supply.

2. Connect the panel to the unit TY29 through the proper cable.

3. Place the actuator 1mm far from the sensor S1, measure the exact distance with the

gauge.

4. Adjust RV1 until a voltage of 0V can be read on the digital voltmeter at the terminal 2.

5. Check that there is 0V also at the standard output.

6. Adjust RV3 to obtain 1V at the proportional output.

7. Place the actuator 4mm far from the sensor S1, measure the exact distance with the

gauge.

8. Adjust RV2 until a voltage of 3V can be obtained at the terminal 2.

9. Check that there is a value of +8V at the standard output and +4V at the proportional

output.

10. After calibration, insert the voltmeter between the terminal 1 and the ground.

11. Vary the distance of the actuator through the proper knob by steps of 0.5mm; then

measure the corresponding actual distance with the gauge regarding the value of the

output voltage on the digital voltmeter.

12. Tabulate the resulting data.

13. Plot data on the graph.

Observations:

No. L (mm) Vout (V)