Mechatronics Lab Manual

VIDYA PRATISHTHAN’S

COLLEGE OF ENGINEERING, BARAMATI

DEPARTMENT OF MECHANICAL ENGINEERING

LABORATORY MANUAL

SUBJECT: MECHATRONICS [SUBJECT CODE: 302050]

CLASS: T.E. MECHANICAL

YEAR: 2011-12

APPROVED BY:

H.o.D. [Mech] PRINCIPAL

Prof. P. R. Chitragar Dr. S. B. Deosarkar

VALIDITY UP TO: ACADEMIC YEAR 2012 – 2013

PRAPARED BY: PROF. D. D. Rupanwar

VIDYA PRATISHTHAN’S

COLLEGE OF ENGINEERING, BARAMATI


List of Experiments

FACULTY: PROF.D. D. RUPANWAR SUBJECT: MECHATRONICS

YEAR: 2011-12 CLASS: T.E. (MECH)

1. Study of Displacement Measurement (LVDT)

2. Study of Load Cells

3. Study and Verification of P, I, D, P+I, P+D, P+I+D control actions

4. Development of Ladder diagram / programming PLC for bottle filling Plant.

5. Study of Thermocouples and RTD

6. Study of Switches and Relays

7. Study of Various Actuators

8. Study of Flip flops and Timers

9. Study of Applications of Op-Amp circuits

10. Study of A/D and D/A converters

Industrial Visit Report on study of PLC and PID

Prof. D. D. RUPANWAR

[Lab-Incharge]

MECHATRONICS-LABORATORY MANUAL

DEPARTMENT OF MECHANICAL ENGINEERING-VPCOE

EXPERIMENT NO. 1

TITLE: LINEAR VARIABLE DISPLACEMENT TRANSFORMER

AIM: To study input output characteristics of Linear Variable Displacement

Transformer.

APPARATUS: Linear Variable Displacement Transformer.

THEORY:

LVDT Trainer

Scientech LVDT Trainer ST2303 is designed to learn LVDT characterstics.LVDT(Linear

variable Differential Transformer) is the most widely used inductive transducers for

displacement measurement. LVDT is a secondary transducers which converts the

displacement directly into electrical output proportional to the displacement. The trainer

has seven segment LED display showing displacement in mm with sensitivity of

10mv/mm in the range of 10mm.ST2303 is self contained single box design and easy to

use.

Features

Self contained and easy to operate.

Sensitive, Linear Stable and Accurate.

Functional block indicated on broad mimic

3 digit LED display with polarity indicator.

Onboard LVDT displacement measurement jig with micrometer.

Amplitude measurement for Excitation Generator. High repeatability and reliability.

Compact size.

Experiment

that can be

performed

Study of Input and Output characteristics of LVDT.

To determine linear range of operation of LVDT.

To determine sensitivity of LVDT.

To measure Phase difference between LVDT

secondaries



It is used for measurement of displacement. LVDTs operate on the principal of a

transformer. LVDT consists of a coil assembly & a core. The coil assembly is typically

mounted to a stationary form, while the cored is secured to the object whose position is

being measured. The coil assembly consists of three coils of wire would on the hollow

form. A core of permeable material can slide freely through the center of the form. The

inner coil is the primary, which is excited by an AC source as shown. Magnetic flux

produced by the primary is coupled to the two secondary coils, including an AC voltage

in coil.

The main advantage of LVDT over the other types of displacement transducer is the high

degree of robustness. Because there is no physical contact across sensing element, there

is no wear in the sensing element. Because the device relies on the coupling of magnetic

flux, an LVDT can have infinite resolution. Therefore the smallest fraction of movement

can be detected by suitable signal conditioning hardware, and the resolution of the

transducer is solely determined by the resolution of the data acquisition system.



LVDT MEASUREMENT: LVDT measures displacement by associating a signal value

for any given position of core. This association of signal value to a position occur through

electromagnetic coupling of an AC excitation value signal on the primary winding to the

core & back to the secondary winding. The position of the core determines how tightly

the signal of the primary coil is coupled to each of the secondary coils. The two

secondary coils are series-opposed, which means wound in series but in opposite

directions. This results in the two signals on each secondary being 180o out phase.

Fig .depicts a cross sectional view of LVDT. The core causes the magnetic field general

by primary winding to be coupled to the secondary. When the core is centered perfectly

between both secondary & the primary the voltage induced in each secondary is equal in

amplitude & 180oout of phase. Thus the LVDT output is zero because the voltages cancel

each other.

Displacing the core to the left causes the first secondary to be more strongly coupled to

the primary than the second secondary. The resulting higher voltage of the first secondary

in relation to the second secondary causes an output voltage that is in phase with primary

voltage likewise. Displacing the core to the right causes the secondary to be more

strongly coupled to the primary than the first secondary. The greater voltage of the

second secondary causes an output voltage to be out of phase with the primary voltage.

FEATURES & APPLICATION: Its features & benefits are as follows

1. FRICTION FREE OPERATION: One of the most important features of an LVDT

is its friction free operation. In normal use, there is no mechanical contact between

the LVDT core & coil assembly so there is no rubbing, dragging, or other source of

friction.

2. INFINITE RESOLUTION: Since an LVDT operates on electromagnetic coupling

principle in friction–free structure, it can measure infinitesimally small change in core

position. This infinite resolution capability is limited only by the noise in an LVDT

signal conditioner & the output display’s resolution.



3. UNLIMITED MECHANICAL LIFE: This factor is especially important in high

reliability applications such as air –craft, satellites & space vehicles & nuclear

installations. It is also highly desirable in many industrial process control & factory

automation systems.

4. SINGLE AXIS SENSITIVITY: An LVDT responds to motion of the core along the

coils axis but is generally insensitive to cross position thus on LVDT can usually function

without observe effect in application involving misaligned or floating mooing member.

5. NEW POINT REPEATABILITY: The location of LVDT‘s intrinsic null point is

extremely stable & repeatable, even over wide operating temperature range. This makes

an LVDT perform well, as a null position sensors in closed –loop control system & high

performance servo balance instruments.

6. FAST DYNAMICS RESPONSE: The absence of friction during ordinary operation

permits an LVDT to respond very fast to changes in core position. The dynamics

response of an LVDT sensor itself is limited only by the inertial effect of the core’s slight

mass.

7. ABSOLUTE OUTPUTS: An LVDT is an absolute output device, as opposed to an

incremental output device. This means that in the event of loss of power, the position data

being sent form the LVDT will not be lost.



FUNCTIONAL DESCRIPTION OF BLOCKS:

1. LVDT MEASUREMENT JIG: It is enclosed in M.S. enclose with arrangement of

two hexagonal nuts that can be rotated clockwise or anticlockwise to set the reading on

display to 0.0 at 10mm position on micrometer. LVDT core is attached to the micrometer

spindle.

2. MICROMETER: The micrometer provides displacement to the LVDT core. The

displacement suffered by core is indicated by 3 1\2 digit LED display in mm. It will be

same as read on micrometer. The main scale of micrometer is at 25mm. Least count of

main scale is 1mm. Circular scale on thimble is of 1mm with least count 0.01mm. On one

circular rotation of thimble, the spindle will display LVDT core 1mm.

3. EXCITATION GENERATOR: The output of excitation generator is 4 KHz sine

wave of variable amplitude. It is used to excite primary coils of LVDT. The max input

given to primary of LVDT is 4V p-p, which can be set by an amplifier preset given in the

Excitation generator block.

4. BUFFER: It is used to improve current driving capacity of excitation generator so that

excitation generator can drive low impedance primary coil of LVDT.

5. SIGNAL CONDITIONER: - It is used to process the form or mode of a signals so as

to make it intelligible to, or compatible with, a given devices, including such a

manipulation as pulse shaping, pulse clipping, compensating digitalizing etc. It consists

of rectifier & filter section for each secondary coil.

6. DIFFERENTIAL AMPLIFIER: It is OPAMP based differential amplifier block. It

converts the differential output of signal conditioner block to the single ended output,

which can be used as input to some recording stage to record the data. The output is same

as indicated by display.

7. DISPLAY: It is 3 1\2 digit LED display. It shows displacement of core in mm with

polarity indication. +ve sign shows, core is moved inside & -ve sign shows it is moved

outside the LVDT.



PROCEDURE:

1. Switch on the trainer. Make micrometer to read 10mm i.e. rotate thimble till 0 of the

circular scale coincides with 10 of main scale

2. Display will indicate 0.0 this is the position when core is at the center i.e. equal flux

linking to both the secondary.

3. If display is not 0.0 then adjust display reading 0.0 then adjust display reading to 0.0

with the help of hexagonal arrangement given with the LVDT.

4. Rotate thimble clockwise so that micrometer read 9.9mm. It will move core 0.1 mm

inside the LVDT and simultaneously observe reading on display. It will indicate

displacement from 10 mm position in positive direction. The reading will be positive

it indicates that secondary - I is at higher voltage than secondary-II.

5. Repeat above step by rotating thimble again clockwise by 0.1mm. Reading will be

taken after each 0.1 mm rotation until micrometer read 0 mm. This is positive end.

6. Rotate thimble anticlockwise so that micrometer read 10mm. The display will be 0.0

(center).

7. Rotate thimble anticlockwise so that micrometer read 10.1mm. It will move core 0.1

mm outside the LVDT and simultaneously observe reading on display. It will

indicate displacement from 10 mm position in negative direction. The reading will be

negative.

8. Repeat above steps by rotating thimble again anticlockwise by 0.1 mm. Reading will

be taken after each 0.1 mm rotation until micrometer is 20mm. This is negative end.

9. Compare above results with the observation table

10. Plot the graph between displacement (mm) indicated by micrometer & display

reading (mm) the graph will be linear as shown in diagram.



OBSERVATION TABLE:

SR.NO. DISPLACEMENT INDICATED

BY MICROMETER (mm)

DISPLAY READING

(mm)

01 00 + 10

02 01 + 09

03 02 + 08

04 03 + 07

05 04 + 06

06 05 + 05

07 06 + 04

08 07 + 03

09 08 + 02

10 09 + 01

11 10 00

12 11 - 01

13 12 - 02

14 13 - 03

15 14 - 04

16 15 - 05

17 16 - 06

18 17 - 07

19 18 - 08

20 19 - 09

21 20 - 10



DISPLAY READING

DISPLACEMENT INDICATED BY MICROMETER

CONCLUSION: In this way we have studied input output characteristics of LVDT

trainer.

0 10 20 5 15

+1

0 -10



EXPERIMENT NO. 2

TITLE: LOAD CELL TRAINER

AIM: To study load cell trainer.

APPARATUS: Load cell trainer consisting of

a) Load cell

b) Mechanical stand and pan with cantilever strip.

c) Electronics exciter with digital indicator.

d) Weight ranging from 20gm to 500grams.

THEORY:

Transducers play very important role in the engineering applications. It is

essential to measure parameters like weight, force, pressure, temperature and so

on frequently, for which transducers are required. Strain gauge is one of the

prime transducer widely used in industry for measurements of weight, load,

force, pressure, displacement, indirectly for torque, stress and strain. The

property of material used for strain gauges is, change in resistance when expose

to mechanical or physical change in its shape. The strain gauge foils are available

with different resistance values, different sizes and different gauge factors.

(Gauge factor is the ratio of change in resistance with elongation or strain).

Normally strain gauges are available with 120Ω, 240Ω, 330Ω resistance values.

Resistance wire stain gauges are transducers applied to the surface of structural

members under test in order to sense the elongation or strain due to applied

loads. The setup consists of mild steel structural strip duly ground from both the

side ensuring smooth surface rigidly mounted on a sturdy solid square bar

supported on heavy stable base structure. The sturdy structure stand ensures

better result.



Strain gauge sensor of plastic foil type with 120Ω resistance and 8mm

gauge length, 5mm width, compensated for mild steel type are pasted to steel

strip. The pasting procedure is very important as it is directly related to

elongation of strain gauges when load is applied. Perfect surface contact shall

give us better and consistent change in resistance linear to load applied on it. The

strain gauges changes its resistance with variation of temperature. The change in

resistance is too small in value which makes it difficult in sensing the change. In

view of this the strain gauges are used in the form of bridge and electronic signal

generated is processed by instrumentation amplifier. Bridge may have only one

arm or two arms or four arms strain gauges as active element and balance

resistances as passive element. Two arm strain gauge bridge is the option

preferred on performance basis. We use two strain gauges as active bridge

elements and other two 120Ω passive resistor. The strain gauges are pasted to

steel strips in such a way that one strain gauge sensor is compressed while other

is elongated, resulting in differential change in resistance, increasing the

sensitivity. One strain gauge pasted from top to the strip and another exactly

below from bottom, both the strain gauges are wired with passive resistors in the

form of bridge and terminated at bottom plate on a connector ,makes it easy for

connection. Small pan hooked up to the dead end cantilever with weights.

TYPES OF LOAD CELLS:

HYDRAULIC LOAD CELL: Figure shows the cross section of the hydraulic

load cell. The cell uses the conventional piston and cylinder arrangement. The

piston doesn’t come actually in contact with the cylinder wall in the normal

sense, but a thin elastic diaphragm or bridge ring, of steel is used as the

positive cell, which allows small piston movement. Mechanical stop prevents

the seal from being overstrained. The cell is filled with oil. When the force act

on the piston, the resulting oil pressure is transmitted to some pressure



sensing device like Bourdon gauge, electrical pressure transducers can also be

used to obtain an electrical output. If the load cell is completely filled with oil,

very small transfer or flow is required. Piston movements may be less than

0.05 mm at full capacity. This feature is responsible for good dynamic

response for the system. However the overall response is largely determined

by the response of the pressure sensing element. A problem with hydraulic

cell using conventional piston and cylinder arrangement is that the friction

between the piston and cylinder wall and required packing and seals is

unpredictable.

PNEUMATIC LOAD CELL: A typical pneumatic cell is as shown in figure.

This cell uses a diaphragm of a flexible material and is designed to

automatically regulate the balancing pressure. The air pressure is supplied to

one side of the diaphragm and is allowed to escape through position

controlling bleed valve. Pressure under the diaphragm is therefore controlled

both by the source pressure and bleed valve position. The diaphragm tries to

take up the position that will result in just the proper air pressure to support

the load. This naturally assumes that the supply pressure is large enough so

that its value multiplied by effective area will at least equal to the load.

PIEZOELECTRIC LOAD CELL: In this type of cell, piezoelectric crystal is

used for dynamic force measurement. Such transducers are very sensitive and

used over a wide range. They are used for measuring impact type of dynamic

load.

PRECAUTIONS:

1) Connect the electronic unit to main 230V AC and turn it ON.

2) Place the mechanical stand horizontal and on firm platform.

3) Connect the bridge wire to electronic unit.



4) Ensure proper connections.

5) Gently press the cantilever down and observe the change on electronics

display, if change noted then unit is properly connected.

6) Wait to stabilize and warm up for five minutes.

EXPERIMENTAL PROCEDURE:

1) Ensure that connections are proper and electronic display responds gentle

pressure at cantilever.

2) Adjust ‘0.0’ reading on display with empty pan hooked.

3) Measure bridge excitation voltage on DMM.

4) Observe bridge output on DMM.

5) Place calibration weight in pan and observe the display reading.

6) Keep on adding the weight and record the reading.

7) Reverse the procedure by removing the weight one by one.

CONCLUSION: Hence we have studied load cell trainer. We found that there is

a slight difference in increasing weight response and reducing weight response.



EXPERIMENT NO. 3

TITLE: P+I+D CONTROLLER

AIM: To study and verify different control actions such as On-Off control, Proportional

control, Derivative control, Integral control, Proportional + Derivative control,

Proportional + Integral, Proportional + Integral + Derivative control with a temperature

controller.

APPARATUS: Temperature controller

PID Trainer



THEORY: A controller is a device which compares the output of a system with the

required conditions and converts the error signal into control action, designated to

reduce the error in a closed loop control system. The error might arrive due to changes

in the conditions being controlled or due to change in set value.

TYPES OF CONTROL ACTIONS:

1. ON –OFF/TWO STEP MODE CONTROL: In a two step mode the controller is just a

switch which is activated by the error signal and supplies just an on-off

correcting signal. It is a discontinuous control action. A consequence of this is

that oscillations of the controlled variable about the required condition occur.

Two step control action tends to be used where changes are taking place very

slowly i.e. with a process with a large capacitance. On-off controllers are not

restricted to mechanical switches such as bimetallic strips, the thyristor circuits

can also be employed for rapid switching. This control mode is not precise as it

involves oscillations with long periodic times.

2. PROPORTIONAL CONTROL: With the proportional mode, the size of the

controller output is proportional to the size of the error signal. It means that

correction element receives a signal which is equal to the size of the correction

required. Fig. shows how the output of such a controller varies with the size and

sign of the error. The linear relationship between controller output and error

tends to exist for a specific portion of the graph, which is known as proportional

band. With in the proportional band the equation of the straight line is

represented as

Change in controller output from set point = Kp e

Where e is the error and Kp is a constant known as proportional constant. Kp is

thus the gradient of the straight line. The controller output is generally

expressed in terms of percentage of the full range of possible outputs within the

proportional band. Generally a 50% controller output is specified for zero error.

It is not possible to achieve the change in the percent output of controller with

the change in set value with zero error setting. It requires a permanent error



setting called offset. The size of the offset is proportional to the size of load

changes and inversely proportional to Kp, so a higher value of Kp gives more

steeper graph. This mode is utilized in processes where the value of transfer

function can be increased large enough so as to reduce the offset to an

acceptable level.

3. DERIVATIVE CONTROL: With the derivative mode of control the change in

controller output from set point is proportional to the rate of change with time

of error signal. This can be represented by the equation

Iout - IO = KD de/dt

Where IO set point output value and Iout is the output value that will occur

when the error is e is changing at the rate de/dt. It is usual to express these

controller outputs as percentage of the full range of the output and the error as

the percentage of full range. With the derivative mode as the error signal

begins to change there can be a quite large output since it is proportional to the

rate of change of error signal and not the value of error signal. Fig. shows a

controller output that results when there is a constant rate of change of error

signal with time. The controller output is constant as the rate of change is also

constant and occurs immediately as the deviation occurs. Derivative mode is

not suitable for steady state error signals.

4. INTEGRAL CONTROL: The integral mode of control is one where the rate of

change of the control output I is proportional to the error signal e.

dI/dt = KI e

Figure illustrates the action of integral controller when there is a constant error

input to the controller. When the controller output is constant the error is zero,

the graph can be analyzed in two ways.

PRECAUTIONS:

Ensure the PID trainer is connected to 230 V AC mains.

Ensure no any error detected while self diagnostic check during power ON.

Ensure the Proper mode of control action is selected.

Ensure the Proper PID constants are programmed.

Ensure the Proper set point is programmed.



PROCEDURE:

I. Connect the PID trainer to 230 V AC mains.

II. Turn ON the mains & observe self diagnostic tests.

III. Ensure no error while self diagnostic check.

IV. Set appropriate PID constants

V. Set OUT% Output percentage to 100%

VI. Set proper Set value

VII. Select the controller mode; refer the PID controller mode selection chart

VIII. Note the observations

IX. Give step change to SV

X. Repeat from step VIII

PID CONTROLLER MODE SELECTION:

SR.NO.

TYPE OF CONTROL ACTION

PROPORTIONAL CONSTANT

INTEGRAL CONSTANT

DERIVATIVE CONSTANT

01 On-Off Control 0 0 0

02 Proportional Control 0-200% 0 0

03 Derivative Control 0 0 0-900 Seconds

04 Integral Control 0 0-3600 Seconds 0

05 Proportional +

Derivative Control

0-200% 0 0-900 Seconds

06 Proportional +

Integral Control

0-200% 0-3600 Seconds 0

07 Proportional +

Integral + Derivative Control

0-200% 0-3600 Seconds 0-900 Seconds



BLOCK DIAGRAM OF PID TRAINER SYSTEM: STUDY OF DIFFERENT CONTROL ACTIONS:-

TEMPERATURE SENSOR K-TYPE

THERMOCOUPLE

PROCESS VALUE PID

SET VALUE

THYRISTERISED

MODULE

HEATER

MUFFLE

FURNACE

(Temp. sensor input

to PID)

(Output of PID to T.M.)

(T.M. Controls the Heater)

(Heating the Muffle Furnace)

FAN

(FAN FOR COOLING OR

DISTURBANCE)

FURNACE

TEMPERATURE

Thy. Module

PID

Controller PV

SV

F

A

N

SET

Keyboard

Muffle Furnace

Display

OUT



S=200 205 210 215 220 225 230

P=0 3.6 0 0 3.6 3.6 3.6

I=0 0 35 0 55 0 55

D=0 0 0 14 0 14 47

Time(sec) Temp

(degree

celsius)

Temp

Using P

Temp

Using I

Temp

Using D

Temp

Using

P+I

Temp

Using

P+D

Temp

Using

P+I+D

20 191.2 201.9 198 224.1 218.4 199.2 226.1

40 203.1 191.4 192.7 212.9 213 195.6 229.5

60 204 187.5 199.1 204.7 215.8 200.1 228.4

80 188 194.5 207.3 215.8 227.4 196.3 231.4

100 185.3 201.3 199.5 277.7 230.4 200.3 228.6

120 194.3 197.4 192.2 221.6 219.5 197 231.9

140 204.6 201.3 198.4 208 207.6 200 228.6

160 201.9 197.4 206.8 208.4 207.8 198.6 231.9

180 186.8 188.2 201.8 222.6 221.1 199.9 228.6

200 186 189.6 192.3 227.7 228.6 199.5 231.9

220 195.6 198.5 196.8 216.5 219.8 198.7 228

240 205.9 210.1 205.5 205.1 206.4 200.7 232.3

260 200.7 193.1 202.6 211.7 207.7 197.7 223

280 185.2 187.4 192.5 227 221.6 201.3 231.9

300 188.1 193.5 196 226 228.8 197.3 228

320 197.9 200.8 203.6 213.7 220.5 201.3 231.8

340 206.9 198.3 204.4 204.7 207 197.2 228.2

360 196.5 189.1 193.1 214.9 207 201.0 231.8

380 184 187.9 194.6 228.7 206.6 197.6 228.2

400 188.9 198.7 202.2 223.2 220.2 200.2 231.5

420 199.4 201.2 202.6 210.4 229.3 199.3 229.2

440 206 192.7 195 206.1 222.2 198.9 231.2

460 193.6 187.8 194 219.5 208.1 199.8 229.8

480 184.2 194 200.7 228.9 205.7 197.2 230.4

500 191.1 201.3 207 220.5 219.6 201.1 230.6

520 201.6 197.8 197.4 207.3 228.9 196.8 225.1

540 205.3 188.6 192.1 208 208.1 201.7 230.8

560 190.8 190.1 198.1 223.2 205.6 197.1 228.7

580 184.8 198.8 205.8 228.3 220.7 201 231.4

600 193 201.4 201.6 217.2 229.1 199.2 228



1: Temperature V/S Time:-

2: Temperature Using P V/S Time:



3: Temperature Using I V/S Time:

4: : Temperature Using D V/S Time:



5: Temperature Using P+I V/S Time:

6: Temperature Using P+D V/S

Time:



7: Temperature Using I+P+D V/S Time:

CONCLUSION: Hence we have studied different control actions for a temperature

controller. We have found that the best control action is Proportional + Derivative +

Integral.



EXPERIMENT NO. 4

TITLE: LADDER DIAGRAM AND PLC PROGRAMMING

AIM: Study of Mechatronics system with development of ladder diagram & PLC

programming for bottle filling plant.

APPARATUS: Bottle filling plant trainer model, Allen bradly make PLC loaded with

programme.

THEORY: A] INTRODUCTION TO PLC: Basic structure in beverage industries & petrochemical

industries where the product is in the liquid form such as cold drinking, milk product

etc. Depending upon the product different types of cans, glass bottles, paper cartoons

are used for filling product. So it is necessary to design a plant comfortable for metallic

& non metallic devices.

Fig. shows bottle filling plant which consist of following parts.

1] Conveyor belt driven with servomotor.

2] Proximity switches- inductive and capacitive to sense the metal and nonmetal.

3] Tank containing liquid which is to be filled by motor.

4] Output indicating LEDs

5] Load sensing devices (Circuit switches)





B] PLC (Allen Bradly): PLC uses both analog & digital input & gives the same output to

different channels. For analog and digital input, output programming logic in PLC is

supplied by ladder programming using software RD logos.

C] BOTTLE FILLING PLANT: By changing the time of timers inbuilt in PLC it is

possible to fill different volumes of liquid into the bottles. A fast, accurate & steady

filling is insured by properly setting time count in the timer by using the word accurate.

It means that the liquid is delivered exactly into the bottle without spoilage of liquid

outside the bottle. The operating parameter such as quantity of liquid, movement of

bottle on the conveyor, filling head opening & filling speed for different bottle sizes can

be taken care of by PLC interfacing with plant model. Auto protecting features as

alignment & orientation of bottles passing on conveyor is important. Proximity sensor

used in this model can also be used for position sensing of bottles. The bottles are then

placed & passed for position sensing. This would make, filled bottle is passed through

conveyor by passing through filling programme, when presence of liquid in bottle is



detected. The systems is timed, so that the bottle is moved on the conveyor to filling

unit in fixed time & before filling unit it mainly consist of solenoid valve, submersible

pump & floating sensor.

Solenoid valve opens & water beverage begins to flow through plastic fill

nozzle. The bottle stays in position for programmed time. After bottle gets filled the

conveyor moves & allows the next bottle to set into position.

1] CONVEYOR: It is belt connected to chassis of an AC ‘servomotor’ & it rotates with

rotation of motor. Object is to be placed on the belt then it is moved towards filling

section.

2] PROXIMITY SWITCHES: To confirm that object is properly placed in perfect position

or not, proximity switches are used. It detects the appearance of subject in front of them.

For metallic objects inductive switches are used & for non-metallic object capacitive

switches are used.

3] FILTERS: Filters are used on the top of AC pump assembly. 4] OUTPUT INDICATOR: LEDs used for identification of different operations such as

filling, fault finding etc.

5] LOAD SENSING DEVICES: In case of partially filled bottles comes on belt conveyor,

that bottle is passes as it is, without filtering.

PROCEDURE: 1) Download program of filling on PLC.

2) Make input and output connections.

3) Keep bottle on conveyor and press start switch.

4) When bottle comes in front of proximity switch conveyor belt will stop.

5) The bottle filling will start up to predetermined time as per logic.

6) Same procedure is repeated further for each bottle.



LADDER DIAGRAM



CONCLUSION: Hence we have studied Mechatronics system with development of

ladder diagram & PLC programming for bottle filling plant.

MECHATRONICE-LABORATORY MANUAL


EXPERIMENT NO. 5

TITLE: RTD AND THERMOCOUPLES

AIM: 1. To study the characteristics of RTD .

2. To study the characteristics of J , K and PT100 type of thermocouples.

APPARATUS: 1) Thermocouple & RTD characteristics trainer.

2) Digital Multi Meter.

3) J & K thermocouple, PT100 RTD.

THEORY:

RTD Trainer



PT100 Thermocouple RTD: It is resistance temperature detector. The resistance of a conductor changes with

change in temperature, this property is utilized for measurement of temperature. The

variation of resistance with temperature is represented by following relationships for

most of the metals.

R = R0 [1+ 1T + 2 T+……..+ n T]

R0 = Resistance at temperature T = 0

1, 2, n = Constants

Platinum is especially suited for this purpose, as it can withstand the high temperatures

while maintaining high stability. The requirements of a good conductor material to be

used in RTD are

1. The change in the resistance of material per unit change in temperature should

be less as large as possible.

2. The material should have a high value of resistively so that minimum volume of

material should be used for the construction of RTD.

3. The resistance of the material should have a continuous and stable relationship

with temperature.



The most common RTD’s are made of platinum, nickel or nickel alloys. The economical

nickel wires are used for a limited range of temperatures. Metals most commonly used

for resistance thermometer along with their properties are listed below.

METAL

RESISTANCE

TEMPERATURE

COEFFICIENT

TEMPERATURE RANGE

OC MELTING

POINT OC MIN MAX

PLATINUM 0.39 -260 110 1773

COPPER 0.39 0 180 1083

NICKEL 0.62 -220 300 1435

TUNGSTEN 0.45 -200 1000 3370

THERMOCOUPLE:

If two different metals are joined together, a potential difference occurs across one of the

junction, if another junction is heated. The potential difference depends on the metals

used and the temperature difference between the junctions. If both the junctions are at

same temperature then there will not be net emf produced. Thermocouples are most

important temperature sensors used in industries. Thermocouples are generally

mounted on a sheath to give them mechanical and chemical protection. The type of

sheath used depends on the temperature, at which the thermocouple is to be used. The

best metal thermocouples are E, J, K & T; these are relatively cheap but deteriorate with

the age.

LAWS OF THERMOCOUPLE

LAW OF INTERMEDIATE TEMPERATURE: The emf generated in a thermocouple

with junctions at temperatures T1 & T3 is equal to the sum of emf generated by similar

thermocouples one acting between T1 & T2 and other between T2 & T3, when T2 lies

between T1 & T2.



LAW OF INTERMEDIATE MATERIAL: If a third wire introduced in between two

conductors, the emf generated remains unaltered if the two new junctions are at same

temperature.

PRECAUTIONS: Ensure the following points for proper functioning of the trainer.

1) Mains supply is 1 230VAC 10% 50HZ.

2) Furnace is off and sensor is in place.

3) Fan is off and away from furnace

4) Sensor under calibration is removed from furnace.

EXPERIMENTAL PROCEDURE:

1) Ensure mains supply is 1 230VAC 10% 50HZ.

2) Turn off the fan and furnace

3) Connect the trainer to mains and turn on the trainer

4) Ensure the digital temperature indicator displays room temperature or

appropriate temperature i.e. furnace temp.

5) Give desired set point on digital temp controller

6) Insert sensor in the furnace and connect it to the Digital Multi Meter on

appropriate range.

7) Turn the furnace on and note sensor output as per observation table.

8) If required to restrict furnace temperature, switch off the furnace at any point.

Furnace temp shall latch with over shoot of around 60-800C

9) Also turn on the fan to reduce furnace temperature, if required.



OBSERVATION TABLE:

A] J & K THERMOCOUPLE SENSOR

Measure thermocouple output in mV on DMM range 0-200mV.

[SAMPLE READINGS, ROOM TEMPERATURE 26OC]

SR.

NO.

FURNACE TEMP

[0C]

J THERMO COUPLE

OUTPUT IN

[mV]

K THERMO COUPLE

OUTPUT IN

[mV]

1 30 1 0.15

2 40 1.1 0.17

3 50 1.14 0.2

4 60 1.23 0.22

5 70 1.56 0.24

6 80 1.89 0.26

7 90 2.19 0.29

8 100 2.51 0.43

9 110 2.86 0.54

10 120 3.13 0.67

11 130 3.56 0.83

12 140 3.87 0.95

13 150 4.36 1.07

14 160 4.75 1.27

15 170 5.21 1.41

16 180 6.21 1.59

17 190 6.36 1.79

18 200 6.64 1.98

19 210 7.08 2.21

20 220 7.45 2.42

21 230 7.78 2.63



22 240 8.33 2.85

23 250 8.76 3.06

24 260 9.14 3.27

25 270 9.7 3.49

26 280 10.1 3.71

27 290 10.59 3.95

28 300 10.81 4.14

29 310 11.42 4.38

30 320 11.83 4.57

31 330 12.27 4.79

32 340 12.72 5.01

33 350 13.13 5.22

34 360 13.44 5.43

35 370 13.66 5.66

36 380 14.08 5.87

37 390 14.82 6.09

38 400 15.27 6.29

39 410 15.56 6.5

40 420 16.06 9.71

41 430 16.52 6.94

42 440 16.96 7.15

43 450 17.37 7.37

44 460 17.81 7.61

45 470 18.26 7.83

46 480 18.62 7.83

47 490 19.07 8.06

48 500 19.27 8.3



J-THERMOCOUPLE CHARACTERISTICS

0

5

10

15

20

25

0 100 200 300 400 500 600

TEMPERATURE

VO

LT

AG

E

K-THERMPCOUPLE CHARACTERISTICS

0

1

2

3

4

5

6

7

8

9

0 100 200 300 400 500 600

TEMPERATURE

VO

LT

AG

E



RTD PLATINUM 100 SENSOR:

Measure RTD output in Ω on DMM range 0-200 Ω.

SR.

NO.

FURNACE TEMP

[0C]

RTD OUTPUT R

IN Ω

RESISTANCE

CALCULATED RC [Ω]

1 90 123.85 100

2 100 124.28 103.85

3 110 124.83 107.7

4 120 125.58 111.55

5 130 126.59 115.4

6 140 127.57 119.25

7 150 128.7 123.1

8 160 129.88 126.95

9 170 131.8 130.8

10 180 132.83 134.65

11 190 133.82 138.5

12 200 134.97 142.35

13 210 136.62 146.2

14 220 137.99 150.05

15 230 139.65 153.9

16 240 140.08 157.75

17 250 142.6 161.6

18 260 143.96 165.45

19 270 146.52 169.3

20 280 147.5 173.15



21 290 148.66 177

22 300 150.07 180.85

23 310 151.72 184.7

24 320 153.74 188.55

25 330 154.23 192.4

26 340 157.07 196.25

27 350 158.84 200.1

28 360 160.6 203.95

29 370 162.45 207.8

30 380 164.49 211.65

31 390 165.34 215.5

32 400 168.47 219.35

SAMPLE CALCULATIONS:

Rc = 100 (1+ 0.00385[T-TO]) FOR SAMPLE READING AT T=120 R IS 125.58 AND T-TO IS 120-30 =90 SO RC = 100 ( 1+0.00385 [120-90] ) RC= 111.55



PLATINUM 100 RTD CHARACTERISTICS

0

50

100

150

200

250

0 100 200 300 400 500

TEMPERATURE

RE

SIS

TA

NC

E

CONCLUSION: Hence we have studied characteristics of J & K thermocouple and platinum100 RTD.



EXPERIMENT NO. 6

TITLE: RELAYS AND SWITCHES

AIM: To study the relay & switches.

THEORY:

SWITCHES: Mechanical switches consist of one or more pair of contacts which can be

mechanically closed or open and doing so make a brake electrical circuit. Thus 0 or 1

Signal can be transmitted by the act of opening or closing a switch.

Mechanical switches are classified in term of their poles & throws. Poles are the no of

separate circuit that can be completed by some switching action & throws are the

number of individual contacts for each pole.

SOLID STATE SWITCHES: There are no of solid state switches which can be used to

electronically switch circuit. These includes

1. Diode

2. Thyristor & Triaes

3. Bipolar Transistor

4. Power MOSFETS

DIODE: Diode allows the significant current in one direction only. A diode can be

regarded as directional element only passing a current when forward biased. If the

diode is reverse biased, i.e. for a very high voltage, it will break down. If an AC voltage

is applied to diode it can be regarded as only switching ON when the direction of the

voltage is forward biased and being OFF when the reversed biased. The result is that



the current through the diode is half- rectified to become just the current due to positive

halves of the input voltage.

THYRISTORS: The thyristor of silicon controlled rectifier (SCR) can be regarded as a

diode which has a gate controlling, the conditions under which the diode can be

switched ON with the gate current zero. The thyristor passes negligible current when

reversed biased. When forward biased, the current is also negligible until forward

breakdown voltage exceeds. When this occurs voltage across the diode falls to a low

level about 1 to 2 volt.

I

v

DIODE CHARACTERISTICS

FORWARD BAISED

REVERSE BAISED



BIPOLAR TRANSISTOR: It is of two type’s 1.NPN 2.PNP .In NPN transistor the

main current flows in, at the collector & out as a emitter & vice versa for PNP. For NPN

transistor, so connected to termed as common emitter circuit, when base current IB is

zero, transistor is cut off. In this state both the base –emitter & base collector junction

are reverse biased, relationship bet Ic & Vce is as shown in graph.

MOSFETS (Metal oxide field effect transistor): It has two type

1.N–CHANNEL

2. P-CHANNEL. In this no current is flowing into gate to exercise the control. The

gate voltage is controlling signal with the MOSFETS very high frequency switching is

possible up to 1 MHz.

PROXIMITY SWITCHES: There are number of form of switches which can be

activated by the presence of an object in order to give a proximity sensor with an output

which is either ON or OFF. The micro switch is a small electrical switch which requires

physical contact and a small operating force to close the contact.

e.g. Determining the presence of an item on a conveyor belt, this might be actuated by

the weight of the item on the belt and hence spring loaded plate from under it. The

movement of this platform closes the switch. This type of switches is widely used for

checking the closing and opening of door.

HALF WAVE RECTIFIER





TIMED SWITCHES: Consider a simple requirement for a device which switches ON

some actuator e.g. motor for some prescribed work. A mechanical solution could

involve a rotating cam. The cam would be rotated at a constant rate and follower used

to activate a switch. The length of time for which the switch is closed, depends on the

shape of the cam.

DEBOUNCING: A problem that occurs with mechanical switch bounce, when a

mechanical switch is switched to close the contacts. We have one contact being moved

towards the other. It hits the other end & because the contacting elements are elastic, it

may bounce for number of times before finally settling to its closed state. It might

appear that, perhaps two or more separate switch actions have occurred. Similarly

when a mechanical switch is opened, bouncing can occur.

KEYPADS: A keypad is an array of switches, perhaps the keyboard of a computer or

the touch input membrane pad for some device such as micro wave oven. A contact

type of the form generally used with a keyboard is shown depressing the key plunger,

force together with spring returning the key to the position when key is released. A



typical membrane switch is built up from two water thick plastic films, on which

conductive layers have been printed. These layers are separated by a space layer, when

the switch area of the membrane is pressed.

RELAYS: Relays are electrochemical switches. A relay is basically formed by a coil &

one or more pair of contacts as shown in fig. When a voltage is applied to the coil, the

current flow creates a magnetic field that attracts the contact & closes the switch. If the

current across the coil is cut, the magnetic field disappears & the contact can be

triggered On & OFF by current passing across the coil. The important properties can be

noted in this arrangement.

1 .The controlled circuit is completely isolated from the control circuit.

2. We can apply low voltage & low current to the relay coil to control high voltage or

high current circuit.



CONTROL RELAYS: Relays can be used for much than just as an energy level

translator. e.g. Figure shows a relay used as a latch, where a green light is ON when the

relay is not latches & a red light is ON when the relay is latched. In this case when the

normally open push button switch is depressed, control relay R11 is energized. But

when its normally open, contact closes by passing so that the relay stay closed. Thus it is

latched to de energized.

SPECIAL TYPE OF RELAYS:

LATCH RELAYS: Latch or bistable relays are turned on by a current flowing in the

direction & they maintain the ON state even when the current is cut to turn OFF the

relay. It is necessary to apply another current to the coil, but in the opposite direction.

Some latch relay uses two coils, when one to turn ON & the other turn OFF.

SOLID STATE RELAY: These are special types, in which the contacts are replaced by

some kind of solid state switch such as transistor, SCR, TRIAC or other devices.

REED REAYS: These are relays formed by reed switch & a coil in the configuration

shown in fig. The operational principle is same as that of common relays, when current



flows through the coil, the resulting magnetic field acts on the contacts of the reed

switches & closes them. Reed relays are small are small & very sensitive but can’t

handle large currents.

HOW RELAYS ARE USED: When using relays we have both the devices that is to be

controlled & circuit that will drive the relay.

BY USING CONTACTS: In fig A, we show the simplest application of the relay. It is

used as an SPST switch to control an external load. The load is ON when current flows

across the coil. In fig B, Here we show how the normally closed contacts can be used to

turn a load OFF, when the relay is energized .This configuration is preferred. When the

load on time exceeds the OFF time. Fig C shows the DPDT relay can be used to control

the direction of the current flowing across a load. When the relay is OFF, the direction

of current is I1. When relay is ON the direction is I2

CONCLUSION: Hence we have studied different types of relays and switches.



EXPERIMENT NO. 7

TITLE: TYPES OF ACTUATORS

AIM: To study the Actuators.

THEORY:

ACTUATORS: Ina control system the element which transforms the output of

controller into a controlling action / motion is called as actuators.Actuatros product

physical changes such as linear motors, hydraulic cylinders, pneumatic cylinders and

motors .Actuators can handle the static or dynamic loads placed on it by control valve

the important aspects of actuators are are proper selection and sizing

FUNCATIONS OF ACTUATORS :

An actuator has two major functions.

1) To respond an external signal directed to it causing inner valve to move

accordingly hence to control flow rate of fluid by positioning the control valve.

2) To provide support for valve accessories e.g. limit switches, solenoid valves.

CLASSIFICATION OF ACTUATOR :

Actuators are available in various forms to suit the particular requirement process

control. It can be classified into three main categories.

1. Pneumatic actuators

2. Hydraulic actuators





3. Electrical actuators

PNEUMATIC ACTUATORS:

Pneumatic system used compressed air as working fluid. Pneumatic signal are used

to actual large values and other high power control device. Pneumatic actuators can

produce large force or torque.

TYPE OF PNEUMATIC ACTUATORS:-

There are to types of pneumatic actuators

1. Diaphragm actuator

2. Piston actuators



PISTON ACTUATORS:

Piston actuator is also know as cylinder actuator the cylinder actuator can over

come the high pressure drops when used in with value positioned. The air pressure

alone or spring cylinder combination is used for proportioning or positioning

control values.

TYPES OF PISTON ACTUATORS:

There are two types of piston actuators

1. Single acting piston actuator.

2. Double acting piston actuator.

HYDRAULIC ACTUATORS:

Hydraulic actuators are preferred where large forces are required the basic principal

is same as pneumatic actuators except the working fluid used in hydraulic actuators

an incompressible fluid is used to develop the pressure this pressure can be made

very large by adjustment of the area of the forcing piston .Mostly used fluid in

hydraulic actuators is oil pressurized oil is provided by a pump driven by an electric

motor.

Pressurized fluid drives a piston in a cylinder where the conversion of energy of

compressed fluid into mechanical work is done. A cylinder hydraulic actuator is a

linear type actuator.

TYPE OF HYDRAULIC CYLINDER ACTUATORS:

The hydraulic cylinder actuator can be of two types –

1. Single acting cylinder.

2. Double acting cylinder.



ELECTRICAL ACTUATOR:

Electrical actuator requires electrical signal for its operation the electrical signal can

be AC or DC type electrical actuator works on the principal of electromagnetic

induction commonly used electrical actuators are solenoid relay AC motor, DC

motor etc.

APPLICATIONS

1. Control of air for use in pneumatic cylinder.

2. Control of oil for use in hydraulic cylinder.

3. In home appliances washing machine valves.

4. Commercial use – For measuring oil, kerosene etc.

5. Automobile – Latches (doors)



EXPERIMENT NO. 8

TITLE: TYPES OF FLIP-FLOPS. AIM: To study different types of Flip-Flops.

APPARATUS: Different types of Flip-Flops.

THEORY:

SEQUENTIAL LOGIC: Combinational logic devices generate an output based on the

input values independent of the input timing. With sequential logic devices however,

the timing or sequencing of the input signals is important. Device in this class include

flip-flops, counters, mono stables, latches and more complex devices such as

microprocessors. Sequential logic devices usually respond to inputs when a separate

trigger signal transitions from one level to another. The trigger signal is usually referred

to as the clock (CK) signal. The clock signal can be a periodic square wave or a periodic

collection of pulses. Fig. illustrates edge terminology in relation to a clock pulse where

an arrow is used to indicate edges where state transitions occur. Positive edge triggered

devise respond to low-to-`high (0 to 1) transition and negative edge triggered devices

respond to a high to low (1 to 0) transition.

FIG: CLOCK PULSE EDGES

FLIP-FLOPS: Since digital data is stored in the form of bits, digital memory devices

such as computer Random access memory (RAM) require a means for storing and

switching between two binary states. A flip-flop is a sequential logic device that can

perform this function. The flip flop is called bi-stable devices since it has two and only a

two possible stable out put states: 1 (high) and (low). It has the capability of remaining

0

1

LOGIC LEVEL: HIGH

LEVEL: LOW

-VE EDGE -VE EDGE

+VE EDGE +VE EDGE



in a particular output State. This is the basis of all semiconductor information storage

and processing in digital computer; in fact, flip-flops performs many of the basic

function critical to the operation of almost all digital devices

RS FLIP-FLOP: A fundamental flip flop, an RS flip flop, is schematically shown in fig

below. S is the set input, r is the reset input, and Q and Q1 are the complementary

output. Most of the flip-flops include both outputs where one out put is the inverse

(NOT) of the other. The RS flip flop operates based on the following rules.

1. As long as the input S and R are the both 0, output of flip-flop remains unchanged.

2. When S is 0 and R is 1, the flip-flop is reset to Q=1 and Ộ1=0.

3. When S is 0 and R is 1, the flip-flop is reset to Q=0 and Ộ1=1.

4. It is “not allowed (NA) to place a 1 on S and R simultaneously since the out put will

be unpredictable.

Fig. RS FLIP-FLOP INTERNAL DESIGN



A truth table is a valuable tool for describing the functionality of flip-flops. The truth

table for basic RS flip flop is given in table; Q0 is the values of the output before the

indicated input condition were established. 1 is logic high and 0 is low. The NA is the

last row indicates that the input condition for that row is not allowed. Because we are

precluded from applying the S=1 R-1 input condition. The RS flip flop is seldom used in

actual designs. Other more versatile flip-flops that avoid the NA limitation are

presented in subsequent sections. To understand how flip flops and other sequential

logic circuits function, look at the internal design of an RS flip flop illustrated in fig. It

consists of combinational logic gates with internal feedback from the output to input of

the NAND gates. Fig. illustrates the timing of various signals, which are affected by

very short propagation delays through the NAND gates. Immediately after signal R

transitions from 0 to 1, the input to the lower NAND gate are 0 and Q, which is still 1.

This changes Q1 to 1 after a slight prorogation delay dt1. Feedback of Q1 to the top

NAND gate drives Q to 0 after a slight delay dt2. Now the flip flop is reset, and it

remains in this state even after R returns to 0. The set operation functions in a similar

manner. The propagation delays dt1 and dt2

are usually in the Nano second range. All sequential logic devices depend on feed back

and propagation delays their operation.

TABLE: TRUTH TABLE FOR RS FLIP-FLOP

INPUTS OUTPUTS

S R Q Q1

0 0 QO QO

1 0 1 0

0 1 0 1

1 1 NA



Fig. TIMING DIAGRAM RS FLIP-FLOP S R Q dt1 dt2 Q1

TRIGGERING OF FLIP-FLOPS: Flip-flop is usually clocked; that is a master signal in

the circuit coordinates the changes of the output state of the devices. This allows design

of complex circuits such as a microprocessor where all system changes are triggered by

a common clock signal. This is called synchronous operation since changes in state are

coordinated by the clock pulses. The output of different types of clocked can change on

either a positive edge or a negative edge of a clock pulse. These flip flops are termed

edge triggered flip flops. Positive edge triggering is indicated schematically by a small

angle bracket on the clock input to the flip-flop. Negative edge triggering is indicated

schematically by small circle and angle bracket on the clock input.

The function of the edge triggered RS flip flop is defined by the following rules

1. If S and R are both 0 when the clock edge is encountered, the output state remains

unchanged.

2. If S is 1 and R is 0 when the clock edge is encountered the flip-flop output is set to 1. If

the output is at 1 already, there is no change

3. If S is 0 and R is 1 when clock edge is encountered, the flip-flop output is reset to 0. If

the output is at 0 already there is no change.

4. S and R should never both be 1 when the clock edge is encountered



Fig: POSITIVE EDGE TRIGGERED Fig: NEGATIVE EDGE TRIGGERED

The truth table for a positive edge triggered RS flip flop is given in table below. The up

arrow in the clock (CK) column represents the positive edge transition from 0 to 1. The

NA is in the second to the last row indicates that the input condition for that row is not

allowed. As long as there is no positive edge transition, the values of S and R have no

effect on the output as shown by the x symbols in the last row of the table. A timing

diagram is shown in fig.

TABLE: POSITIVE EDGE TRIGGERED RS FLIP-FLOP TRUTH TABLE

S R CK Q Q1

0 0 QO QO1

1 0 1 0

0 1 0 1

1 1 NA

X X 0,1 QO QO1

S Q

Q1 R

CK

S Q

Q1 R

CK



There are special devices that are not edge triggered in the way just described. An

important example is called a latch.

D FLIP FLOP: The D flip-flop, also called as data flip flop, has a signal input D whose

value is stored and presented at the output Q at the edge of the clock pulse. A positive

edge triggered D flip-flop is illustrated in fig. and its truth table is given in table. Unlike

a latch D flip flop dose not exhibit transparency. The out put changes only when

triggered by appropriate clock edge

Fig: POSITIVE EDGE TRIGGERED D FLIP-FLOP JK FLIP FLOP: The JK flip-flop is similar to the RS flip-flop, where the J is analogous to

the S input and the K analogous to the R input. The major difference is that the J and K

inputs may both be high simultaneously. This causes the output to toggle which means

the output changes to opposite state. The schematics representation and truth for a

negative edge triggered JK flip flop are shown in fig. In table the first two rows of the

table describe the present or clear functions that can be used to initialize the output of

the flip- flop. The third row precludes setting and clearing simultaneously. The symbol

down arrow represents the negative edge of the clock Signal which causes the change in

the output. The last row describes the memory feature of the flip flop in the absence of

negative edge. The JK flip flop has a wind range of applications and all flip-flops can

easily be constructed from it, with proper external wiring.

Q

Q1 R

CK

D



The T toggle flip-flop serves as good example of this. The T flip- flop simply

toggles the output every time it is triggered. The preset and clear functions are

necessary to provide direct control over the output since the T input alone provides no

mechanism for initialization of the output value. The truth table is given in table

Fig: NEGATIVE EDGE TRIGGERED JK FLIP-FLOP

J Q

Q1 K

CK

PRESET

CLEAR



TABLE: NEGATIVE EDGE TRIGGERED JK FLIP-FLOP TRUTH TABLE

CONCLUSION: Hence we have studied different types of flip-flops.

PRESET CLEAR CK J K Q Q1

0 1 X X X 1 0

1 0 X X X 0 1

0 0 NA

1 1 0 0 QO QO1

1 1 1 0 1 0

1 1 0 1 V 1

1 1 1 1 TOGGLE

1 1 0,1 X X QO QO1



EXPERIMENT NO. 9

TITLE: OPERATIONAL AMPLIFIER CIRCUIT AND ITS APPLICATIONS.

AIM: To study Operational Amplifier circuit and its applications in different modes.

APPARATUS: Operational Amplifier THEORY: The term operational amplifier, abbreviated op amp, was coined in the 1940s

to refer to a special kind of amplifier that, by proper selection of external components,

can be configured to perform a variety of mathematical operations. Early op amps were

made from vacuum tubes consuming lots of space and energy. Later op amps were

made smaller by implementing them with discrete transistors. Today, op amps are

monolithic integrated circuits, highly efficient and cost effective. An amplifier has an

input port and an output port. In a linear amplifier,

Output signal = A * input signal



Where A is the amplification factor or gain. Depending on the nature of input and

output signals, we can have four types of amplifier gain, Voltage (voltage out/voltage

in), Current (current out/current in), Transresistance (voltage out/current in), and

Transconductance (current out/voltage in)

741 OPERATIONAL AMPLIFIER: The 741 is a general-purpose operational

amplifier featuring offset-voltage null capability. The high common-mode input voltage

range and the absence of latch-up make the amplifier ideal for voltage-follower

applications. The device is short-circuit protected and the internal frequency

compensation ensures stability without external components. A low value

potentiometer may be connected between the offset null inputs to null out the offset

voltage. The 741C is characterized for operation from 0°C to 70°C. The 741I is

characterized for operation from –40°C to 85°C. The 741M is characterized for

operation over the full military temperature range of –55°C to 125°C.

IDEAL OPERATIONAL AMPLIFIER: Ideal operational amplifiers have infinite gain. If

the voltage at the +ve terminal is larger than the voltage at the –ve terminal then the

output voltage will increase until it reaches the positive power supply. Likewise, if the

voltage at the +ve terminal is smaller than the voltage at the -ve terminal then the

output voltage will decrease until it reaches the negative power supply. Of course, if

both terminals are equal, the output will no longer be driven by the op amp. These



characteristics allow feedback to be used in order to drive the output of the op amp to a

useful value.

Gain: The primary function of an amplifier is to amplify, so the more gain the better. It

can always be reduced with external circuitry, so we assume gain to be infinite.

Input Impedance: Input impedance is assumed to be infinite. This is so the driving

source won’t be affected by power being drawn by the ideal operational amplifier.

Output Impedance: The output impedance of the ideal operational amplifier is assumed

to be zero. It then can supply as much current as necessary to the load being driven.

Response Time: The output must occur at the same time as the inverting input so the

response time is assumed to be zero. Phase shift will be 180°. Frequency response will

be flat and bandwidth infinite because AC will be simply a rapidly varying DC level to

the ideal amplifier.

Offset: The amplifier output will be zero when a zero signal appears between the

inverting and non-inverting inputs.

NON INVERTING AMPLIFIER: Non inverting amplifiers are very powerful because

you can amplify a signal without having a negative rail (depending on the op amp’s

specifications). When a voltage is applied to Vin, Vout begins to rise because of the

infinite amplification. This rising voltage is consequently applied across the voltage

divider of R1 and R2 in such a way that the voltage at the negative terminal of the op

amp begins to rise as well. Once the voltage at the negative terminal has reached the

same value as the positive terminal, the amplification stops and Vout remains constant. If

for some reason the output voltage is pushed further up, the voltage at R1 will go up

causing the op amp to have a negative voltage across it and pull Vout back down again.

The formula expressing the ideal Vout is

Vout = Vin (R1+R2/R1)



NON INVERTING PEAK DETECTOR: Peak detectors allow you to determine the

highest voltage value that a signal produces over a period of time. The one shown here

does not do precisely this, but for many slowly varying signals it is good enough. The

diode located at the output of the op amp allows the op amp to add charge to the

capacitor C while not allowing it to discharge the capacitor. Because of this, Vout will

rise until both the -ve and +ve terminals of the op amp are equal. Then, if Vin drops, the

op amp will no longer be pumping charge into the capacitor, and the resistor R will

allow charge to slowly escape and the voltage at Vout to drop. R and C must be picked

based on how fast you want Vout to drop after detecting a peak.



INVERTING AMPLIFIER: Inverting amplifiers invert your signal and, as a result,

require a negative power supply (assuming Vin is positive). In this circuit, the current

flowing from Vin goes through both R1 and R2. As you can see from the location of the

+ve and -ve terminals, the op amp will pull down Vout until the voltage at the –ve

terminal is equal to ground. Once this happens Vout can be found by the following

equation

Vout Vin [R2/R1]

INVERTING VOLTAGE ADDER: The inverting voltage adder is based on the exact

same principle as the inverting amplifier. The op amp pulls Vout down such that the -ve

terminal is the same as ground and the currents produced by V1 and V2 both add at the

negative terminal and produce a summed voltage drop across the third resistor on the

way to Vout. Thus Vout can be calculated by the following equation

Vout = - (V1 + V2)

Additional voltage inputs can also be tied to the -ve terminal if necessary.



INTEGRATOR: If a capacitor is used as the feedback element in the inverting

amplifier, shown in figure, the result is an integrator. An intuitive grasp of the

integrator action may be obtained from the statement under the section, “Current

Output,” that current through the feedback loop charges the capacitor and is stored

there as a voltage from the output to ground. This is a voltage input current integrator.

DIFFERENTIATOR: Using a capacitor as the input element to the inverting amplifier,

figure, yields a differentiator circuit. Consideration of the device in next figure will give

a feeling for the differentiator circuit. It should be mentioned that of all the circuits

presented in this section, the differentiator is the one that will operate least successfully

with real components. The capacitive input makes it particularly susceptible to random

noise and special techniques will be required for remedying this effect.



CONCLUSION: Hence we have studied a basic operational amplifier and its

applications in various modes.


DEPARTMENT OF MECHANICAL EGINEERING-VPCOE

EXPERIMENT NO. 10

TITLE: ANALOG TO DIGITAL AND DIGITAL TO ANALOG CONVERTER

AIM: To study Analog to Digital and Digital to Analog Converter.

THEORY:

ANALOG TO DIGITAL CONVERTERS: A/D converters are designed based on a

number of different principles: successive approximation, flash or parallel encoding,

single slope and dual slope integration, switched capacitor and delta sigma. We

considered the first two because they occur most often in commercial designs. The

successive approximation A/D converter is Very widely used because it is relatively

fast and cheap. It uses a D/A converter (DAC) in a feedback loop. DAC’s are described

in the next section. When the start signal is applied, the sample and hold (S&H)

amplifier latches the analog input. Then the control unit begins interactive process, the

digital value is approximated, converted to an analog value with the D/A converter,

and compared to the analog input with the computer. When the D/A converter output

equal to the analog input, the end signal is set by control unit and the correct digital

output is available at the output. If ‘n is the resolution of A/D converter it take n steps

to complete the conversion. More specifically ,input is compared to combinational of

binary fraction (1/2 ¼ 1/8 …………..,1/2 N) of the full scale (FS) value of the A/D

converter. The control unit first turns on the most significant bit (MSB) of the register,

leaving all lesser bits at the 0, and the comparator test the DAC output against the

analog input. If the analog input exceeds DAC output, the MSB is left on (high);

otherwise, it is reset to 0. This procedure is then applied to the next lesser significant

bits and comparison is made again. After n comparisons have occurred, the converter is

down to the least significant bits (LSB). The output of the DAC then represents the best

digital approximation to the analog input. When the process terminates, the control unit

sets end signal signifying the end of conversion. As an example, a 4 bits successive

approximation procedure is illustrated graphically. The MSB is 1/2 FS, which in this



case is grater than the signal; therefore, the bit is turned off. The second bit is ¼ FS and

is less than the signal so it is left ON, The third bit is given ¼+1/8 of FS which is still

less then the analog signal, so the third bit is left on. The fourth provide (1/4+1/8+1/16)

of FS and is greeter than the signal, so the fourth bit is turned OFF and the conversion is

completed. The digital result is 0110. Higher resolution would produce a more accurate

value. An n bits successive approximation A/D converter has a conversion time of n dt,

where dt is the cycle time for 12 bits successive approximation A/D converters range

form 1 to 100 micron. The faster type of A/D converter is known as a flash converter.

As fig illustrates, it consist of bank of input comparators acting parallel to identify the

signal level. The output of the latches is in a coded form easily converted to the required

binary output with combinational logic. The flash converter illustrated in fig is a 2 bit

converter having resolution of four output states. Table listed the comparator output

coded and corresponding binary output for each of the state assuming an input voltage

range of 0 to 4v. The voltage range is set by the Vmin and Vmax supply voltage shown

in fig. The code converter is simple combinational logic circuit. For the 2 bit converter

the relationship between the codes bites Gi and binary bits Bi are

B0 = G0.G1+ G2

B1 = G1



Several analog signals can be digitized by single A/D converter if the analog signals are

multiplexed at the input to the A/D converter. An analog multiplexer simply switches

among several analog input using transistors or relay and control Signals. This can

significantly reduce cost of the system design. In addition to cost other parameter

important is selecting an A/D converter is the input voltage range, resolution, and

conversion time.

DIGITAL TO ANALOG (D/A) CONVERSION: Often we need to reverse the process

of A/D conversion by changing digital value to analog voltage. This is called digital to

analog conversion. A D/A converter allow a computer or other digital devices to

interface with external analog circuit and devices. The simplest type of D/A converter

is resistor ladder network connected to an inverting summer op amp circuit as shown in

fig. This particular converter is a 4 bits R-2R resistor ladder network. It differs form

others possible resistor ladder network, in that it requires two precision resistance

value. The digital input to the DAC is a 4 bits binary number represented by bits b0 b1 b2

and b3 where b0 is least significant bit and b3 is the most significant bits. Each bit in the

circuit controls a switch between ground and the inverting input of the op amp.



To understand how analog output voltage Vout related to the input binary number we

can analyze the four different input combinations 0001 0010 0100 and 1000 and apply

the principle of the super position for arbitrary 4 bits binary numbers. If the binary

number is 0001, the b0 switch is connected to the op amp and the other bits switches are

grounded. The resulting circuit as shown in fig. Switches are grounded, since the non

inverting input of the op amp is grounded, the inverting input is at the virtual ground.

The resistance between node V0 and ground is R, which is parallel combination of two

2R value. Therefore, V0 is the result of voltage division of V1across two series resister of

equal value R



CONCLUSION: Hence we have studied A/D and D/A converter.

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Mechatronics Lab Manual