01_sharing_eepw 2320_2nd sem_2015-16

8/18/2019 01_Sharing_EEPW 2320_2nd Sem_2015-16

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EEPW 2320

Instrumentation Measurement Techniques

Introduction to INSTRUMENTATION (Outcome No–

1),SENSORS and Transducers (Outcome No – 7),

Analog Instruments (Outcome No – 2),

Digital Instruments (Outcome No – 4),

Prepared by:

Mr. Arun.S.Gopinath & Mr: Y.Ameer Hamza

Lecturer , Electrical Section

Shinas College of Technology

Updated by:Mr. Mahesh. C

Lecturer, Electrical Section

Shinas College of TechnologyText Books:Fundamentals of all Industrial instrumentation & process control, William C Dunn, Mc Graw Hill, Edition 2005

Reference Books:

1. “Electrical and Electronic Measurement” By A K Sawhney, Dhanpat Rai & sons, 9th edition 2. “Electrical & Electronics Measurements and Instrumentation”, R. K. Rajput, S Chand Technical

http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744


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OBJECTIVES OUTCOMES

Prerequisites: EETE 2102 and EEPW2150

Course Goals: To provide the working principles and applications of different types of measuring instrumentsand transducers along with their applications

This course should enable the student to:

1. Understand the operation, principles and

characteristics of functional elements in

engineering. Advanced measurement

Techniques.

2. Perceive the principle of operation of

Instrumentation systems.

3. Grasp the techniques of electrical

measurements and know the range and

limitations of measuring instruments.

4. Know the principle of operation of varioustypes of electrical transducers.

5. Understand the operation of Data Acquisition

System and Data Conversion.

6. Know how to maintain and test engineering

measurement systems

A student who satisfactory complete the

course should be able to:

1. Define the functional elements of a typical measurement

system and evaluation of its performance.

2. Be acquainted with the principle of operation and

construction of Analog indicating instruments. Its calibration.

3. Deal with the principle of operation and construction of

Wattmeter and Energy meter. Working of Insulation Megger

4. Get acquainted with the principle of operation and

construction of Digital instruments.

5. Get acquainted with the principle of operation and

construction of cathode ray oscilloscope. Be familiar with the

principle of operation and construction of InstrumentTransformers.

6. Get acquainted with the principle of operation of

Potentiometers. A.C. & D.C. Bridges, Maxwell and Andersons

bridges.

7. Identify various types of sensors and transducers

8. Deal with all types of signal processing and conditioning.

9. Be acquainted with all common analogue and Digital devices

for data presentation.

Course Objective & Outcomes of

Instrumentation & Measurement Techniques (EEPW 2320 )


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COURSE SCHEDULE

of

instrumentation and measurement techniques

EEPW 2320

Day Time Venue Section

Sunday 08:00 to 10:00 AM E 010 (T) 3Tuesday 08:00 to 10:00 AM B 102 (P)

Monday 12:00 to 02:00 PM B 102 (P)2

Wednesday 12:00 to 02:00 PM B 015 (T)

Instrumentation & Measurement Techniques (EEPW 2320) Sem 2, AY 2015-16


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Course Grading Scheme

Course Passing Grade: 67-69 (C grade)*

Marks

Grade

GPA

90-100

A

4.0

85-89

A-

3.7

80-84 B+ 3.3

76-79

B

3.0

73-75 B- 2.7

70-72 C+ 2.3

67-69

C

2.0

60-66

C-

1.7

55-59 D 1.0

Below 55

F

0.0



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Theory + Practical based courses(The course is a combination of theoretical and practical hours (for 2T+2P) contact hours)

Pass Grade: C (67 Marks)

Theory (T) Practical (P)

Quizzes (T): 20 Marks This is divided into two parts:

Structured Assignments (T) / Homework: 10 Marks Part – I : Lab report 60%

Mid Term Examination (T): 20 Marks Part – II : PracticalAssessments

40% Final Examination (T): 50 Marks

Total (Theoretical part): 100 Marks Total (Practical part): 100 Marks

Final Marks (based on credit hour ratio):

2/3 Theoretical part marks + 1/3 Practical part marks

Assessment Method:



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Scheduling of the course (Theory):

NOTE:

A minimum number of four quizzes will be conducted. Best two quiz marks will be

considered for Quiz marks weightage.

No complementary quiz is given to absent student even for any valid excuse

Assignments should be submitted well within the last date. In case of late submission

of assignments, 20% of the marks will be deducted each day (

1mark / day).

Theory (T) Marks Allotted Selection & Scheduled date

Quizzes (Upto 4): 20 Marks Best 2 & Announced Quizzes

Structured Assignments:

(Minimum Two)05 Marks

One before Midterm &

One after Midterm

Mid Term Examination: 20 Marks 3rd Week of Feb 2016

Final Examination: 50 Marks Last week of March 2016

Total Theory Marks TT = 100 Marks



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COURSE ASSESMENT METHOD – contd…

Sl

NoFactors Marks allotted Marks Obtained

1Identification of aim and objectives related theory,formulae and significance

10

2 Ability to follow procedure, data collection 10

3Data analysis, Interpretation of results & conclusions

related to the objectives & course outcomes15

4 Completeness, accuracy and correctness of data andresults (Figures, Graphs, Tables, Units, etc..)

15

5 Submission of Lab report on time 10

Total Marks: 60

Part I - Lab report with data collection and analysis – 60%

The Practical Part is divided into TWO parts:

In this part the student is subjected to frequent written questionnaire about the performedexperiments. The duration of each questionnaire does not exceed 15 Minutes.

Part - II (Practical Assessments) = 40%

Submitted on time

(During next

Practical class)

Submitted after 1 week

(After 2 weeks from the date

of conduction of Experiment)

Submitted after 2 weeks

(After 3 Weeks from the date of

conduction of Experiment)

10 marks 5 marks 0 marks


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Instructions about Lab Report: Each Student has to write a Lab report on each Experiment / Exercise

performed & submit the Lab report on the next week

Submission of the Lab report is only on the day of Practical classes.

But if the student fails to submit the lab report after a week of performing,

he/she will loose 5 marks. And the student has to submit the lab report only

on the next practical class (after a week).

If the student fails to submit the Lab report even after TWO weeks of

performing the experiment, he will loose full TEN marks which is allotted for

the submission of lab report

After the completion of each experiment student must take the signature of

course teacher on the cover page and attach the cover page to each Lab report

before submission.

The report must be written on plane A4 sheets & preferably on both sides of

the paper

Neat Report with all the required data, graph, units and conclusion will get

better marks.Instrumentation & Measurement Techniques (EEPW 2320) Sem 2, AY 2015-16


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Case 1:

The student will lose all lab report marks (60 marks) for that particular lab report if

he/she doesn’t perform that practical at all.

Case 2:

If the student submits excuse to the registration department and removes absence

from the college system, then he / she can perform the experiment, gets

authentication by the concerned technician and submits lab report, then only his/her

lab report for that particular experiment will be evaluated for full marks allocated

(i.e. 60 marks).

Case 3:

If the student is present for the practical and performed the experiment but he/she

didn’t submit lab report , then only 10 marks (for the factor ‘ability to follow

procedure, data collection) will be allotted

If a student is absent for the practical


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Practicals (P) Marks Allotted Scheduled date

Practical

Assessment #1:

10 Marks Each &

The best of 2 will be

considered as the final

Practical marks for a

maximum of

40 Marks

Announced Assessments(Each Assessment is

Conducted after the

completion of 2 or 3

Experiments)

Practical

Assessment #2:

Practical

Assessment #3:

Lab Report

(For each Experiment)60 Marks

Lab Report should be

submitted with in a week

(Submission only on the

practical class)

Total Practical Marks: TP = 100 Marks

Total Marks =2

/3 of TT +1

/3 of TP

Scheduling of the course (Practical’s):

Final Marks(based on credit hour ratio)

2/3 Theory partmarks (TT)

1/3 Practicalpart marks (TP)

= +



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Attendance Criterion:

IMPORTANT NOTE:

If the absence reaches 30%, the student will be debarred from the final exam and will

get ZERO in the final exam.

If the student comes LATE after 10 minutes of the starting time of class, S/he will

not allowed to attend the class

If students are absent without a valid reason, it will be considered as if the topic/s is

already covered and will be included in exams

If a student is absent for two continuous weeks within the semester in all courses,

he/she will be DISMISSED from the college.

Chewing gum is not allowed inside the Class

Use of mobile phones are strictly prohibited inside the Class.

Entering and leaving the Class room must be with the permission of Lecture orTechnician

1st Warning Absent for a total of Three (3) classes

2nd Warning Absent for a total of Six (6) classes

3rd Warning and Debar Absent for a total of Nine (9) classes


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Attendance Excuse:

If a student failed to attend any class, s/he has to submit the original excuse

document within one week from the date of absence to registration department

only. A copy of the excuse letter should be submitted to the course teacher.

If a student failed to attend midterm or final exam, s/he has to fill in a

Supplementary Exam Form attached with the original excuse stamped from

concern authorities and submit it to the registration department within one

week from the exam date. Hospital/Clinic Attendance Certificate is not accepted

as a valid excuse.

The coverage of topics in the midterm supplementary exam will include topics

covered up to the midterm exam + topics covered one week after the midterm

exam.



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Course Withdrawal

A student is allowed to withdraw one course during the semester. The withdrawal period

will end a week after the midterm exam result announcement.

Late Submission of Assignment

20% of assignment scored mark will be reduced for each day of late submission

Cheating

In case of an accusation of cheating during an examination is proven, the following will be

imposed:

Disciplinary Action for Cheating Case/s: First Offense (Zero Mark)

Second Offense (Study Suspension for one semester)

Third Offense (Dismissal from the College)



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Marks Sheet:Course Details

Course

CodeCourse Title (2T+2P) Group No. Course Lecturer Academic Year Semester Credit Points

Passing Marks /

grade

EEPW3257 Power Electronics 1 Mr. MAC 2013-14 3 3 67 / C

Student Details Theory PracticalTOTAL

COURSE

MARK

(TT+TP)

Letter

Grade

Grade

Point

R E MA R K S

SN ID Name

G e n d e r

Course work Mi d t er m

E x am F

i n a l

E x a m ( T )

T o t a l

( T h e o r y ) 2/3

out of

100

theory

marks

Part I

(Report

s)

Part II

(Questionn

-aire) T o t a l

( P r a c t i c a l ) 1/3

out of

100

prac.

marks

Q u i z

m a r k s

(

t l )

A s s i g n m e

n t m a r k s

( T o t a l )

20.0 10.0 20.0 50.0 100.0 TT 60.0 40.0 100.0 TP 100

1 12S345 ABCDEF 18 9 15 35 77 51.3 56 38 94 31.3 82.6 B+ 3.3 Pass

2 456J789 XYZPQR 19 8 17 40 84 56 57 36 93 31 87 A- 3.7 Pass

3 98S562 KLMNOP 15 8 9 25 57 38 55 37 92 30.7 68.7 C 2.0 Pass

4 75J364 GHIJKL 15 7 8 15 45 30 55 37 92 30.7 60.7 C- 1.7 Fail

5

6

7

8

9

10

11

12

Ministry of Manpower

Shinas ollege of Technology

Shinas, Sultanate of Oman



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TEXTBOOKS

Course

code

Course Title Text Book used Outcomes

covered

EEPW2320

Electrical and

Electronic

Measurement

Title Fundamentals of all Industrial

instrumentation & process control

9 / 9 Author William C Dunn ISBN 100071457356

Publisher Mc Graw Hill, Edition 2005

REFRENCE BOOKS

Course

code Course Title

S.

No. Reference Book/s used

Outcomes

covered

EEPW

2320

Electrical and

Electronic

Measurement

1

TitleElectrical & Electronics Measurements

and Instrumentation 9 / 9 Author R. K. Rajput,

ISBN 812192989Publisher S Chand

2

TitleElectrical & Electronics Measurements

and Instrumentation 9 / 9 Author A K Sawhney

ISBN 0750662190

Publisher Dhanpat Raj & sons

http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744http://www.kopykitab.com/Electrical-and-Electronic-Measurement-eBook-By-A-K-Sawhney-isbn-9780000279744


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Chapter Outline Course outcomes covered

Introduction to INSTRUMENTATION

1. Definition & Applications of

INSTRUMENTATION

2. Instrument & Examples for

Instruments

3. Classification of INSTRUMENTs

4. ELEMENTS OF MEASUREMENT

SYSTEM

5. Instrument Performance

Characteristics

6. Parameters of Static characteristics

7. DYNAMIC CHARACTERISTICS

8. Parameters of Dynamic characteristics

Define the functional elements of a typical

measurement system and evaluation of its

performance (Outcome No.1)

Recognize and present real life examples of

the aforementioned concepts and

interrelate some of them (Outcome No. 7)

Describe the link between Electrical and

other sciences

Identify technological applications of some

of the aforementioned concepts

(Outcome No. 8)

Describe how he/she can harness the

benefits of some of the aforementioned

concepts

CHAPTER #1

Introduction to INSTRUMENTATION (Outcome No – 1)



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1 1 Introduction to INSTRUMENTATION

What is Instrumentation?

Instrumentation is the branch of science that deals with measurement and

control in order to increase efficiency and safety in the workplace.


What is the need for instrumentation?

Instrumentation provides the means of monitoring, recording and controlling a

process to maintain it at a desired state

APPLICATIONS OF INSTRUMENTATION


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1.2 INSTRUMENT

What is an Instrument?

• A device used to determine the present value of quantity under measurement

• Any physical device which is meant for measuring or controlling some quantity (or

process) is called as an Instrument


General Examples for Instruments:

• Screwdriver meant for tightening screws

• Spanners for tightening nut and bolts

• Scale or Tape meant for measuring length or distance

Instruments used in Engineering:

• Pressure gauge is meant for finding pressure in the pressure vessel or

working pressure of a Boiler

• Thermometer is meant for measuring temperature

•

Engineering Drafter is meant for developing Engineering drawings

http://www.google.com.om/url?sa=i&source=images&cd=&cad=rja&docid=a1U7mPa_1NNzoM&tbnid=aP27XOxPpe2bAM:&ved=0CAgQjRwwAA&url=http://noida-uttarpradesh.olx.in/engineering-drafter-for-engineering-drawing-omega-brand-for-immediate-sale-iid-439968103&ei=L0ggUuqYFoK4rgfvtoHoAQ&psig=AFQjCNEEOibTP9tLpKodCRupDycflKpkZg&ust=1377933743463055http://www.google.com.om/url?sa=i&source=images&cd=&cad=rja&docid=eTGwmuq3ueqb9M&tbnid=dB5rDlJjJ6Br0M:&ved=0CAgQjRwwAA&url=http://www.solidswiki.com/index.php?title=File:Pressure_gauge.gif&ei=yEYgUtqBHcn5rAeu3oHwBw&psig=AFQjCNHLA5FEi0GquGNE48iebMwjRAPghQ&ust=1377933384583061http://www.google.com.om/url?sa=i&source=images&cd=&cad=rja&docid=YGEkYvvKy9B1GM&tbnid=owzviNVYm5YDSM:&ved=0CAgQjRwwAA&url=http://toolmonger.com/2008/05/02/an-ambidextrous-tape-measure/&ei=SEkgUoyuOIinrAe244H4Bw&psig=AFQjCNG2usr5KlKIIxgg_8Cd1vce3rW8-A&ust=1377934025037433


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Null type Instruments & Deflection type Instruments

Monitoring Instruments & Control (Transmitting) Instruments

Analog Instruments & Digital Instruments

1.3 Classification of INSTRUMENTs

Give the classification of Instruments)


Null type Instruments Deflection type Instruments

In Null type instruments the reference

point will be Null or zero

In Deflection type instruments output value is

observed by the deflection of a needle

Examples: Physical Balance

& Wheatstone Bridge

Examples: Fuel Gauge ,

Analogue Voltmeter/Ammeter

Null type Instruments & Deflection type Instruments


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Monitoring Instruments & Control (Transmitting) Instruments


Monitoring Instruments Control (Transmitting) Instruments

They will just display the value which are

required to analyze

They will transfer the output signal as

feed back in a control system

Examples: ECG, X Rays, Thermometer,

Voltmeter, Ammeter, Wattmeter…. Examples: Thermostat , Thermocouple

Analog Instruments & Digital Instruments

Analog Instruments Digital Instruments

In analog instruments the output signal

can be linear or nonlinear continuousdeflecting type.

In digital instruments the output signal

is a stepped value usually a number

Examples: Deflection type Ammeter,

Voltmeter , Fuel Gauge

Examples: Digital Voltmeter, Digital ammeter,

Digital Speedo meter


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The method of comparison between a known (standard) value and an unknown

value is called as “Measurement”

A system which is used to find the unknown quantity is called as “Measurement

System”


1.4 ELEMENTS OF MEASUREMENT SYSTEM

SENSOR

DISPLAY

RECORD

TRANSMIT

SIGNAL

CONDITIONER

Input – True Value

of Variable

1. Sensor 2. Signal Conditioner 3. Display-Recorder-Transmitting

Definition of MEASUREMENT


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• It takes the signal from the sensor and changes it into a condition which is

suitable for either display or in the case of a control system for use to exercise

control.

• Signal conditioning includes different processes like Amplification, Attenuation,

Filtering, Converting, Isolation and any other processes required to make

sensor output suitable for processing after conditioningExample: Amplifier

AmplifierInput

Signal from Sensor Output

Larger Value Instrumentation & Measurement Techniques (EEPW 2320) Sem 2, AY 2015-16

What is a SIGNAL CONDITIONER

A sensor converters the physical quantity to be measured into a signal

which can be read by an observer or by an instrument.

Definition of

SENSOR Transducer)

DISPLAY DATA PRESENTATION


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• This present the measured value in a form which enable an observer to

recognize it.

• It is the last stage of a measurement system

• This may be via a display system where the output from the signal conditioner

is displayed suitable to read or record the value or other wise transmit to

activate some thing to control.


What is a DISPLAY OR DATA PRESENTATION

Example for a Measurement System


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1 5

Instrument Performance Characteristics

What is Performance Characteristics of an Instrument ?

Set of parameters used to determine the performance of an Instrument is called as

“Performance Characteristics”

What is the importance of Performance characteristics?

The performance characteristics are to be known, to choose an instrument that most

suited to a particular measurement application.

These performance characteristics are also known as system characteristics

The Performance characteristics can be broadly divided into two groups:

1. Static Characteristics

2. Dynamic Characteristics



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Comparison between

static and dynamic Characteristics

Static Characteristics: Dynamic Characteristics :

If the performance of a system remainsalmost constant or vary quite slowly, it is

called as “Static Characteristics”

If the performance of a system varies withrespect to the time, then it indicates

“Dynamic Characteristics’”

Static Characteristics does not depend

on the time

Dynamic Characteristics depends on the

time

Static characteristics can be determinedby calibration.

It gives the relationship between input andoutput of a system along with its dependency

on time

Example:

1. Current through a resistive circuit.

2. Temperature of a city during Summer

Example:

1. Current through a capacitor.

2. Initial Speed of a car

Name some of the parameters that decide ‘Static characteristics’ ?

Parameters of ‘Static characteristics’: Accuracy, Precision, Static errors, Repeatability,

Reproducibility, Span, Range, Off set, Drift, Resolution, Sensitivity…..



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Accuracy: Closeness of the Readings to the true value of the quantity being measured.

Example: A voltmeter is used to measure the voltage across a battery of 10V.

If the voltmeter reads 9.99V and 10.01V [readings are close to true value] then

the instrument is more accurate.

If the voltmeter reads 9.5V and 10.63V [readings are for away to true value] then

the instrument is less accurate.

Static Error: It is the algebraic difference between the measured value and the true

value of the quantity.

Static Error = [True value Measured value] of the quantity.

1.6 Parameters of Static characteristics:

Precision: Ability of the instrument to give same value of reading again and again

for a constant input signal. [Or] In a repeated measurements of same true value,

the degree of closeness is also called as “Precision”


Example for Precision and Accuracy:


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Let us consider three instruments X, Y and Z measuring the same true value of 10

mm. Eight measurements are taken on the same true value for each instrument.

INSTRUMENT Measured values in[mm]

Interpretation

Example for Precision and Accuracy:


X9.91, 9.92, 9.91,

9.94, 9.93, 9.91,

9.95, 9.92

1) All measured values are close to true

vaule so instrument is More accurate.

2) All measured vales are close to each

other so precision is high.

Y9.11, 9.12, 9.11,

9.13, 9.14, 9.12,

9.12, 9.11

1) All measured values are not close to

true vale so instrument is less accurate.

2) All measured vales are close to each

other so precision is high.

Z9.3, 9.2, 9.1, 9.7,

9.5, 9.4, 9.3, 9.6

1) All measured values are not close totrue vale so instrument is less accurate.

2) All measured vales are not close to

each other so precision is also less.


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Example:

The expected value of the voltage across a resistor is 80V. However, the

measurement gives a value of 79V.

Calculate: (i) Absolute Error (ii) % Error (iii) Relative

Accuracy (iv) % of Accuracy

(i) Absolute Error: True value – Measured value =

(ii) % Error =

(iii) Relative Accuracy = 1 – Error =

(iv) % of Accuracy = Accuracy 100% =

%100

TrueValue

ueMeasredValTruevalue


Parameters of Static characteristics Continued


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Repeatability and Reproducibility are the two different methods to check the

precision of the instrument.

Repeatability: It is the closeness of output readings when the same input is applied

repetitively over a short period of time, with the same measurement conditions,

same instrument and observer, same location and same conditions of use

maintained throughout

Reproducibility: It is the closeness of output readings for the same input when thereare changes in the method of measurement, observer, measuring instrument,

location, conditions of use and time of measurement .

Span: It is the algebraic difference between higher calibrated value (Hc) to the

lower calibrated value (Lc) . Span= Hc – Lc

Parameters of Static characteristics….. Continued

Example: A thermometer whose scale goes from 400C to 1000C has a span of:

Span= 1000C –[400C ]=600C.




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Range: An instrument is calibrated to read from the lowest to the highest values. This

operating region is called as “Range”.

Example: A thermometer whose scale goes from -400C to 1000C has a range from -400C

to 1000C.

Offset: It is the reading of an instrument with zero input .

Offset is a Error, which occurs due to poor calibration

Drift: It is the change in an instrument's reading over extended period. Drift occurs mainly due to factors such as time, line voltage, or ambient temperature

effects

Example: Let us consider a micrometer X and Y measures a true vale of 10 mm for three

times each.

INSTRUMENT Measured values in [mm] Interpretation

X 9.91, 9.92, 9.93Each measurement it gives different

value so the instrument has drift

Y 9.91, 9.91, 9.91All measurement it gives same value

so the instrument has no driftInstrumentation & Measurement Techniques (EEPW 2320) Sem 2, AY 2015-16




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Resolution: is the smallest non zero input variable to which the instrument will

respond or measure.

Linearity: is a measure of the proportionality between the actual value of a variable

being measured and the output of the instrument over its operating range.

Hysteresis Error: is the difference in readings obtained when an instrument

approaches a signal from opposite directions. If an instrument reads a midscale value

going from zero it can give a different reading from the value after making a full scale

reading.

Sensitivity: It is a measure of the ratio of change in the output to the change in the

input of the instrument.

Sensitivity = Change in the output signal / change In the input signal.

Example: 1mV recorder has a 20 cm scale of length. assuming the measurement

is linear across the scale ,

Sensitivity can be termed as 20 cm/ 1 mV




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1 7

DYNAMIC CHARACTERISTICS

Dynamic characteristics tell us about how well a system responds to changes in its input

with change in time. For dynamic signals, the sensor or the measurement system must be

able to respond fast enough to keep up with the input signals.

0 1 2 3 4 5 6

Time in Seconds

O u t p u t

1.2

1.0

0.8

0.6

0.4

0.2

0

D e l a

y T i m e ( t d )

t P

Settling Time (t S)

Steady State

Time Constant

Overshoot

0.63

0.5

t r



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On the Dynamic Characteristics given mark the following parameters:


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On the Dynamic Characteristics given mark the following parameters:

(a) Peak Time (b) Settling time (c) Time constant (d) Over shoot

0 1 2 3 4 5

1.25

1.0

0.75

0.5

0.25

0

Time in Seconds

O u

t p u t


For the Dynamic Characteristics given find the value of following parameters:


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0 1 2 3 4 5

1.2

1.0

0.8

0.6

0.4

0.2

Time in Seconds

O u t

p u t

g g

(a) Peak Time (b) Settling time (c) Time constant (d) Over shoot (e) steady state

error at t = 2 Sec


CHAPTER #2


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Definition of Sensors &

Transducers

2.1 Thermocouple

2.2 Thermistor

2.3 Strain Gauge

2.4 Spring Balance

2.5 Venturimeter

• Identify various types of sensors and

transducers (Outcome No.7)

• Recognize and present real life examples of

the aforementioned concepts and interrelate

some of them (Outcome No. 7)

• Identify technological applications of some of

the aforementioned concepts (Outcome No. 8)

• Describe how he/she can harness the benefits

of some of the aforementioned concepts

CHAPTER #2

SENSORS and Transducers (Outcome No – 7)



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A sensor converters the physical quantity to be measured into a signal

which can be read by an observer or by an instrument.

Example for Sensors

1. Thermocouple senses the change in temperature and

gives output as e.m.f. (Voltage) proportional to it

2. Thermistor senses the change in temperature and gives

output as resistance proportional to it

3. Strain gauge senses the change in length or position due

to applied force and gives output as change in resistance

proportional to Force

4. Spring balance senses the change in force and gives a

output as change in displacement proportional to force

5. Venturi meter senses the flow of liquid and gives

difference in pressure proportional to the flow of the

liquid

Definition of

SENSOR

2 1 Thermocouple


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2.1 Thermocouple

Symbol of Thermocouple

Thermocouple is a device used to sense the

change in temperature and gives a output in

terms of Voltage (e.m.f)

Thermocouples are widely used in applications like temperature measurement for kilns, gasturbine exhaust, diesel engines, and other industrial processes. Thermocouples are also

used in homes, offices and businesses places as the temperature sensors in thermostats (it’s

a part of heater or air conditioner), and also as flame sensors in safety devices for gas-

powered major appliances


It produces a voltage when the temperature of one of

the spots differs from the reference temperature atother parts of the circuit. Thermocouples are a widely

used type of temperature sensor for measurement and

control

It is a junction of two different metals like Nickel

and Chromium or Nickel and Copper….

2 2 Thermistor

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2.2 Thermistor

Mainly there are 2 types of Thermistors:

(1) Positive Temperature Coefficient (PTC) Thermistors(2) Negative Temperature Coefficient (NTC) Thermistors

Symbol of Thermistor

Thermistor is a type of resistor whose resistance varies significantly with

temperature, more than compared to standard resistors. This change in resistance

will be proportional to measured Temperature.They are made by Semiconductor materials (Ceramic materials).

• A Positive temperature coefficient (PTC) thermistor causes increase in

resistance with increase in Temperature.

• A Negative temperature coefficient (NTC) thermistor causes decrease in

resistance with increase in Temperature.


2 3 Strain Gauge

http://upload.wikimedia.org/wikipedia/commons/1/10/Thermistor.svg


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• Strain is the amount of deformation of a body due to the

applied force.

2.3 Strain Gauge


• In order to measure the mechanical strain, the mostcommon device used is a strain gauge .

• When the force is applied across the strain gauge, it

causes the deformation to the foil used in it, which in

turn causes its electrical resistance to change.

• This changed resistance is measured using a Wheat-

stone bridge which is related to the strain.

2 4 Spring Balance

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• Used to measure the Force or Mass.

2.4 Spring Balance


• Mass to be measured is kept in the hook provided in the spring

balance.

• Due to force the spring elongate and changes its position over a

calibrated scale showing the weight (mass) in grams

Venturi meter is used to calculate the velocity of fluids (Flow rate) through a pipeline.

2.5 Venturi meter

The fluid may be a liquid or a gas.

Applications of Venturi meter:

It is basically used for measuring the flow rate.

In industries it is used to measure the rate of flow of chemicals through pipe

It is used to measure the flow rates of water, gases, slurries and dirty liquids.

CHAPTER #3

http://upload.wikimedia.org/wikipedia/commons/5/54/Venturifixed2.PNG


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Definition of Analog instruments

3.1 Construction of PMMC Instrument

3.2 Working operation of PMMC

instrument

3.3 Advantages, Disadvantages andapplications of PMMC instrument

3.4 PMMC meter as an Ammeter

3.5 Multi range Ammeter

3.6 PMMC meter as a Voltmeter

3.7 Multi range Voltmeter

3.8 Moving Iron Instruments –

Attraction type MI Instrument

3.9 Repulsion type Moving iron

instrument

• Be acquainted with the principle of operation

and construction of Analog indicating

instruments. Its calibration (Outcome No.2)

• Recognize and present real life examples of

the aforementioned concepts and interrelatesome of them (Outcome No. 7)

• Identify technological applications of some of

the aforementioned concepts (Outcome No.

8)

• Analyze the mathematically the effects of

these instruments

• Describe how he/she can harness the benefits

of some of the aforementioned concepts

CHAPTER #3

SENSORS and Transducers (Outcome No – 2)


ANALOG INSTRUMENTS


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ANALOG INSTRUMENTS

Analog meters are generally electromagnetic devices that drive a pointer

against a scale.

Electric measuring instruments and meters are used to indicate directly the

value of current, voltage, power.

The most common analogue instrument or meter is the Permanent Magnet

Moving Coil instrument (PMMC) and it is used for measuring dc current or

voltage of a electric circuit.

On the other hand, the indications of alternating current ammeters and

voltmeters must represent the RMS values of the current, or voltage.


Torques in the Instruments


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The deflection of any instrument (pointer) is determined by the combined effect of the

deflecting torque, damping torque and controlling torque

Torques in the Instruments

Deflecting Torque causes the instrument movement to rotate from its zero

position. The value of deflecting torque depends on the electrical signal to be

measured.

Damping Torque acts in a direction opposite to the movement of the moving system.

This brings the moving system to rest from the deflected position reasonably quickly

without any oscillation or very small oscillation.

Controlling Torque acts in the opposite sense to the deflecting torque, and the movement will take up an equilibrium or definite position when the deflecting and

controlling torque are equal in magnitude. Spiral springs or gravity usually provides

the controlling torque. Without controlling torque the pointer will not swing back from its

maximum position to zero after removing the sourceInstrumentation & Measurement Techniques (EEPW 2320) Sem 2, AY 2015-16

3.1 Permanent Magnet Moving Coil Instrument [PMMC]


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3.1 Permanent Magnet Moving Coil Instrument [PMMC]Draw and mark the important parts of a PMMC Instrument.

45

Front view of PMMC Diagram of PMMC.

The PMMC instrument consists of:

a) A pointer to show the deflection

b) Moving coil

c) A permanent magnet to provide a magnetic field

d) A Spring to control the pointer

e) A Scale (Dial) to show the reading

f) A Mirror to avoid parallax error.

3.2 Working of PMMC Instrument


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When a current is passed through the coil windings, a torque is developed on

the coil. Torque is produced by the interaction of the magnetic field ofpermanent magnet and the field set up by the current in the coil.

This torque causes the aluminum pointer attached to rotating coil to move.

The pointer moves over the calibrated scale and indicates the deflection of the

coil.

3.2 Working of PMMC Instrument

Explain the working principle of PMMC and also write the uses of various part of it.

Hairsprings are attached to each end of the coil and these hair springs are

useful in controlling the torque.

Sem 2, AY 2014-15

PMMC Instrument


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1) What is Parallax Error in Analog meters?

Measurements made by the observer not having his sight on line with the pointer leads

to “Parallax error”

Example: In the meter, the reading we can see from this position is 76, but the actual reading

will be different and that can be obtained referring to mirror reading which is 78

2) How do you reduce Parallax error in a PMMC?

To reduce parallax error a mirror is usually placed along with the scale, hence while

reading the scale, we should make sure that the pointer comes on line with its reflection

in the mirror

3) What is the purpose of Balance Weight in a pointer?

A balance weight is attached to the pointer to counteract its weight.

4) At what condition the coil rotation will Stop?

When the magnetic force due to permanent magnet & electromagnet becomes equal to

force of the springs, then the coil stops

Force produced by the magnetic fields = Force of the springs.

5) How do you get free movement of coil?

The coil set up is supported on jeweled bearings in order to achieve free movement.

PMMC Instrument

47


3 3 PMMC Instrument


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Advantages of PMMC meters:-

a) Uniform scale.ie, evenly divided scale.

b) High efficiency.

c) Require little power for their operation.

d) Very accurate and reliable.

e) External stray fields have little effects on the readings (as the operating magnetic

field is very strong).

3.3 PMMC Instrument

Disadvantages:-

a) Cannot be used for AC measurements.

b) More expensive (about 50%) than the moving iron instruments because of their

accurate design.

c) Some errors are caused due to variations (with time or temperature) either in

the strength of permanent magnet or in the control spring.

Applications:-

a) In the measurement of direct currents and voltages.

b) In DC galvanometers to detect small currents.

c) In Ballistic galvanometers used for measuring changes of magnetic flux linkages.


3.4 PMMC meter as an Ammeter


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C ete as a ete1. How a PMMC meter can be used as a Ammeter?

When a PMMC meter is connected in series with the components carrying the main

current, it becomes an “ Ammeter”

2. Write the property of Ideal Ammeter.

An Ideal ammeter would be capable of performing the measurement without

changing or distributing the main current in that branch & for this its internal

resistance should be ideally “Zero”

3. What is the effect of internal resistance in the Ammeter?

Practical ammeters would possess some internal resistance.

The ammeter resistance should be very small compared to the load resistance to

avoid any effect of change on the load current .

4. What is the normal current measuring capacity of PMMC ? Why it is low?

Since the coil winding in PMMC meter is small and light , they can carry only small

currents (μA- few mA).


3.5 Multi-range Ammeter RM


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6. What is the Loading of meter?

A meter which is used for measurement should not affect (change) the performance of

the circuit, if it changes the performance of the circuit then it means that the meter is

Loading the circuit. This occurs in Ammeters when its internal resistance is quite high

7. What is the use of Shunt resistor in a Multi range Ammeter?

Measurement of large current requires a shunt external resistor to connect with the

meter movement, so only a fraction of the total current will passes through themeter.

mI

I

R IR

mmSH

5. Draw and Explain the construction of Multi-range Ammeter?

3.5 Multi range Ammeter

R1

R2

R3

R4

A

B

C

D

E

RM

Rm

RSH I

Im

ISH

A multi-range ammeter can be constructed simply

by connecting several values of shunt resistances,

with a rotary switch to select the desired range.


EXAMPLE


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EXAMPLE

A PMMC instrument has a coil resistance of 100Ω and gives a full-scale deflection

(FSD) for a current of 500μ A. Determine the value of shunt resistance required if

the instrument is to be employed as an ammeter with a FSD of 5A.

RM

RSH I

Im

ISH


3.6 PMMC instrument as a Voltmeter


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1. Explain how a PMMC meter can be used as a Voltmeter (Write the properties of a Voltmeter)

By connecting a PMMC meter in parallel with the circuit where the voltage is to be

measured, it can be used as a Voltmeter

A voltmeter should have a very high series resistance Rse.

2. What is the use of connecting a high resistance in series with a Voltmeter?

To minimize voltmeter loading, the voltmeter operating current should be very small i.e.,

the resistance connected in series with the coil should be high.

3. At what condition Voltmeter gives loading effect?

When the internal resistance of Voltmeter is quite low, it gives loading effect

4. How to extend the range of the Voltmeter?

A multi-range voltmeter can be constructed simply by connecting several values of

series resistances, with a rotary switch to select the desired range


3.7 Multi-range Voltmeter


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EXAMPLEA PMMC meter with a coil resistance 100Ω and a full scale deflection current of

100μ A is to be used in the voltmeter circuit as shown in Fig. The voltmeter ranges

are to be 50V, 100 V and 150V. Determine the required value of resistances for

each range.

g

Im

mm

SE

R IVR


A multi-range ammeter can be constructed simply by connecting several values of series

resistances, with a rotary switch to select the desired range

3 8

Moving Iron Instrument


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1. Write the Advantages of the Moving Iron [MI] Instruments?

Moving Iron instruments can work on DC and AC.

These are the cheapest instrument available.

2. Draw and Explain the working principle of Moving Iron instrument.

The signal (voltage or current ) to be measured is applied to a stationary coil.

The magnetic field produced attracts or repulses iron vane causing deflection of the

pointer over calibrated scale.

3. Draw and Explain the Attraction type MI instrument with neat diagram.

Attraction type MI Instrument

It consist of a coil, through which the test current is passed.

A pivoted soft-iron mass attached to the pointer.

The resulting magnetic polarity at the end of the coil nearest

the iron mass then induces the opposite magnetic polarity into

the part of the iron mass nearest the coil, which is then drawn

by attraction towards the coil, deflecting the pointer across a scale


3.9 Repulsion type Moving Iron Instrument


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p yp g

4. Draw and Explain the Repulsion type MI instrument with neat diagram

In repulsion type moving–iron instrument consists of two cylindrical soft iron vanes

mounted within a fixed current-carrying coil.

One iron vane is held fixed to the coil frame and other is free to rotate, carrying with it

the pointer shaft.

Two irons lie in the magnetic field produced by the coil.

Coil consists of only few turns if the instrument is an

ammeter or of many turns if the instrument is a voltmeter.

Current in the coil induces both vanes to become

magnetized and repulsion between the similarly magnetized

vanes produces a proportional deflecting torque for rotation.

Fig. Repulsion type MI Instrument


CHAPTER #4


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Definition of Digital instruments

4.1 Advantages of Digital Instruments

4.2 Block diagram of digital

Instruments

4.3 Comparison between analog and

Digital Instruments PMMC meter

as an Ammeter

4.4 Digital (DMM)

4.5 Block diagram of DigitalMultimeter

4.6 Working of Digital Multimeter

4.7 How to use DMM?

Get acquainted with the principle of operation and

construction of Digital instruments. (Outcome

No.4)

Recognize and present real life examples of the

aforementioned concepts and interrelate some of

them (Outcome No. 7)

Identify technological applications of some of the

aforementioned concepts (Outcome No. 8)

Describe how he/she can harness the benefits of

some of the aforementioned concepts

Digital Instruments (Outcome No – 4)


4.1 Digital Instruments:


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g

1. What are Digital Instruments?

The Digital Instruments use Logic circuits and techniques for carrying out measurement

of quantities and they represent the outputs in digits.

Digital Instruments are rapidly replacing the analog devices due to the flexibility of

usage

i. Easier to design

ii. Easy to store the information

iii. Greater accuracy and precision

iv. Reliable and economical

v. They can display both numbers and alphabets

3. Give the advantages of Digital Instruments.

2. Give the applications of Digital instruments ?

They can be used to measure Voltage, Current, Resistance, Frequency, Time period etc..


4.2 Block diagram of digital Instruments:


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Analog to

Digital

Converter

Signal

ProcessorDisplay

Analog

quantity to

be measured

To enable the digital systems to recognize information / inputs which are analog in nature

must be converted into digital form & this is done using ADCs (Analog to Digital Converters)

Signal Processor: Data in digital form is processed using this signal processor so that it

becomes compatible with display deviceDisplay: The information is presented as series of digits using display units

4. Draw the block diagram of Digital instrument and explain each block

Sl No Parameter Analog Instruments Digital Instruments

1 Accuracy Less More

2 Storing of information Not possible Possible

3 Size Bigger Smaller

4 Cost Less More

5 Power Supply Not required Required

4.3 Comparison between analog and Digital Instruments


4 4 Digital Multimeter


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Multimeter is used to measure AC/DC voltage, AC/DC

current and resistance with digital display.

Features of DMM:

Some of the new digital multi-meters have special features like, checking continuity,

components testing, measurement of hfe, etc..

DMM gives digital display, which is very accurate.

It has an advantage of very high input resistance.

It also provides over ranging indicator i.e. if the unknown electrical quantity increases

beyond measuring capacity it shows ’1’ on the display


Digital Multimeter:


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Constant

Current

Source

Buffer

Amplifier

Calibrated

Attenuator

Current to

Voltage

Converter

Current toVoltage

Converter

Calibrated

Attenuator

Rectifier

Circuit

Analog to

Digital

Converter

Digital Display

R e s i s t a n c e

Rotary Switch

AC I

InputSignal

4.5 Block diagram of Digital Multimeter:

4.6 WORKING OF DIGITAL MULTIMETER:


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To Measure Resistance:

Connect an unknown resistor across its input terminals.

Choose rotary switch to Resistance.

The proportional current flows through the resistor, from constant current source.

According to Ohm’s law voltage is produced across it.

This voltage is directly proportional to its resistance.

This voltage is buffered and fed to A-D converter, to get digital display in Ohms.


To Measure AC Voltage:


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To Measure AC Voltage:

Connect an unknown AC voltage across the input terminals.

Keep rotary switch in position to ‘AC –V’.

The voltage is attenuated, if it is above the selected range and then rectified to convert it

into proportional DC voltage.

It is then fed to A-D converter to get the digital display in Volts

To Measure AC Current:

Current is indirectly measured by converting it into proportional voltage.

Connect an unknown AC current across input terminals.

Keep the switch in position ‘AC-I’.

The current is converted into voltage proportionally with the help of I-V converter and

then rectified.

Now the voltage in terms of AC current is fed to A-D converter to get digital display in

Amperes.


To Measure DC Current:


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To Measure DC Current:

The DC current is also measured indirectly.

Connect an unknown DC current across input terminals.

Keep the switch in position ‘DC - I’. The current is converted into voltage proportionally

with the help of I-V converter.

Now the voltage in terms of DC current is fed to A-D converter to get the digital display

in Amperes.

To Measure DC Voltage:

Connect an unknown DC voltage across input terminals.

Keep the switch in position ‘DC - V’. The voltage is attenuated, if it is above the selected range and then directly fed to A-D

converter to get the digital display in Volts.


4 7 How to use DMM?


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DMM as a Voltmeter:

Remember that while measuring voltage, the DMM is connected in parallel.

To measure voltage at a point in the circuit, first confirm the type of voltage, whether it is

AC or DC.

Also confirm the range of voltage (it is better to start with higher voltage range).

DMM as an Ammeter:

Remember that while measuring current, the DMM is connected in series.

To measure current flowing through a circuit or wire, first confirm the type of current,

whether it is AC or DC.

Also confirm the range of current (it is better to start with higher current range).

DMM as an Ohmmeter:

If you are measuring the unknown value of a resistor already connected in a working

circuit, then first of all, switch off the power supply and disconnect the resistor from the

circuit.

This is very important because if you measure the resistance without disconnecting it

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