Course of Instrumentation

and Measurement

Karim Bourouni

Nat

iona

l Sch

ool o

f Eng

inee

rs o

f Tun

is E

NIT

Dip

l.Dr-

Ing.

(R

.U. E

nerg

etic

of B

uild

ings

and

Sol

ar S

yste

ms)

Indu

stria

l Eng

inee

ring

Dep

artm

ent

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

1

1. In

trod

uctio

n

2. C

hapt

er 1

:E

rror

s of

Mea

sure

men

ts

3. C

hapt

er 2

: S

tatis

tical

Ana

lysi

s

4. C

hapt

er 3

: M

easu

ring

syst

em‘s

per

form

ance

s

5. C

hapt

er 4

: T

empe

ratu

re M

easu

rem

ent

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

Pla

n of

The

Cou

rse

2

Pla

nnin

g of

the

cour

se

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

Ses

sion

1:

�P

rese

ntat

ion

of th

e co

urse

�Introduction

�D

efin

itio

ns;

�R

ecen

t ev

olut

ions

.

�Chapter 1 :Introduction to measurement

�P

refa

ce

�In

trod

ucti

on�

The

ele

ctro

nic

Inst

rum

ent

syst

em

Ses

sion

2:

�Chapter 1 :Introduction to measurement

�T

he e

lect

roni

c In

stru

men

t sy

stem

�Chapter 2 :Measurement and errors

�In

trod

ucti

on

�C

lass

ific

atio

n of

err

ors

Ses

sion

3:

�Chapter 2 :Measurement and errors

�C

lass

ific

atio

n of

err

ors

Ses

sion

4:

�Chapter3 : Statistical Analysis

�In

trod

ucti

on;

�C

hara

cter

isin

g St

atis

tica

l dis

trib

utio

n�

Tot

al M

easu

rem

ent S

yste

m E

rror

s

�R

egre

ssio

n an

alys

is

3

Pla

nnin

g of

the

cour

se

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

Ses

sion

5:

Ses

sion

6:

Ses

sion

7:

Ses

sion

8:

�Serie of Exercises N 1,2

�Chapter 4 : Measuring System perform

ances

�T

he id

eal M

easu

ring

sys

tem

�

Stat

ic C

hara

cter

isti

cs o

f ins

trum

ents

�D

ynam

ic C

hara

cter

isti

cs o

f ins

trum

ents

�Chapter 4 : Measuring System perform

ances

�D

ynam

ic C

hara

cter

isti

cs o

f ins

trum

ents

�Chapter 5 : Temperature Measurement

�In

trod

ucti

on�

Exp

ansi

on M

etho

ds f

or M

easu

ring

tem

pera

ture

s�

Res

ista

nce

The

rmom

eter

s

4

Pla

nnin

g of

the

cour

se

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

Ses

sion

9:

Ses

sion

10:

�T

herm

ocou

ples

�In

tegr

ated

Cir

cuit

s T

empe

ratu

re S

enso

rs

�P

yrom

etry

�Chapter 5 : Temperature Measurement

�Serie of Exercises N 3, 4

5

Pla

n of

exp

erim

ents

1.Li

near

Var

iabl

e D

iffer

entia

l Tra

nsfo

rmer

2.R

otat

iona

l Spe

ed

3.T

herm

opile

4.T

herm

ocou

ple

Cal

ibra

tion

5.O

ptic

al P

yrom

eter

6.R

esis

tanc

e T

empe

ratu

re S

enso

rs

7.T

ime

Con

stan

t

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

6

Intr

oduc

tion

to th

e C

ours

e

1.P

refa

ce

2. In

trod

uctio

n

3. T

he E

lect

roni

c In

stru

men

t Sys

tem

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

7

1.P

refa

ce

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

Impo

rtan

ce o

f Exp

erim

enta

tion

Many areas of basic research

and applied product

development

All phases of Engineering

There is a very defined need

of the engineer to be familiar

with methods of

measurements as well as

analysis techniques for

interpreting experimental

data

Cha

ngem

ent o

f Exp

erim

enta

l tec

hniq

ues

Development of Electronic

devices

More precision is now possible

in the measurement of basic

physical quantities

8

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

Kno

wle

dge

of m

any

engi

neer

ing

prin

cipl

es-Specification of the physical variables to investigate

-Design or procuration of the instrumentation

-Knowledge of the governing principles of the instruments

-Analyze of the experimental data

Res

earc

h in

volv

es a

com

bina

tion

of a

naly

tical

and

ex

perim

enta

l wor

k

-Experimental data are explained or prodicted by analytical

models developed by the theoricians in accordance with

fundamental physical principles

Whe

n ex

perim

enta

l dat

a ar

e en

coun

tere

d w

hich

do

not f

it i

nto

the

sche

me

of e

xixt

ing

phys

ical

theo

ries

-Experimental data are verified

-In some cases the theories are modified or revised to take

the results of new experimental data into account

1.P

refa

ce

9

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

2.In

trod

uctio

nO

bjec

tives

of t

his

cour

se :

Obj

ectiv

es o

f thi

s co

urse

:

Electronic instrumentation systems in a manner sufficiently

complete that the student will acquire an ability to make accurate

and meaningful measurement of mechanical and therm

al

quantities.

The

rmal

qua

ntiti

esM

echa

nica

l qua

ntiti

es

-Temperature

-Radiation

-Heat Flux

-Specific Heat

-Therm

al Conductivity

-Strain

-Force

-Pressure

-Moment

-Torque,…

1 2Methods that are commonly employed to make such measurements

3Some of the elements of an electronic instrumentation system

10

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

Power

Supply

Transducer

Conditioning

circuit

Amplifier

Recorder

Data

Processor

Controller

Command

Generator

11

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

3.1

The

Tra

nsdu

cer

: 3.

1 T

he T

rans

duce

r :

It is an analog device that converts a change in the mechanical or

therm

al quantity being measured into a change of an electrical

quantity.

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

∆ ∆∆∆ε εεε

∆ ∆∆∆R

∆ ∆∆∆V

12

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

3.1.

2 T

he P

assi

ve T

rans

duce

r :

3.1.

2 T

he P

assi

ve T

rans

duce

r :

It’s generally an Impedance which varies when the measurand

varies

�Temperature (resistivity)

�Deform

ation (resistivity)

�Position

�Humidity (Dielectric Constant)

�Level (Dielectric Constant)

Exa

mpl

es :

Exa

mpl

es :

3.1.

1 T

he A

ctiv

e T

rans

duce

r :

3.1.

1 T

he A

ctiv

e T

rans

duce

r :

They act as generators. Such transducers are based on a

physical concept which converts the energy of the «Measurand»

into electrical energy example: photoelectric effect, piezoelectric

effect, photovoltaic effect, etc.

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

13

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

3.2

The

Pow

er S

uppl

y :

3.2

The

Pow

er S

uppl

y :

Provides the energy to drive the transducer

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

Prim

ary

Coi

l

Coi

l 2, S

econ

dary

Coi

l 1, S

econ

dary

Mot

ion

to

be in

dica

ted

Con

stan

t AC

V

olta

ge

Dif

fere

nce

vol

tage

v 0

= v

1 -

v 2

v sPr

imar

yC

ore

Insu

lati

ng

For

m

Core

Seco

ndar

y

Seco

ndar

y

v 1 v 2

v 0

14

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

3.3

The

Sig

nal C

ondi

tione

rs :

3.3

The

Sig

nal C

ondi

tione

rs :

Are electric circuits that convert, compensate or manipulate the

output from the transducer into a more usable electrical quantity

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

�Wheatstone Bridge

Exa

mpl

e :

Exa

mpl

e :

∆ ∆∆∆R∆ ∆∆∆V

e s

Rs

AB

C

D

R1

R3

R2

R4

Rd

i dv m

The bridge is in

equilibrium when V

A=VB

i d= 0

15

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

�They are used when the output from the transducer signal

conditioner is very small (signals of a millivolt or less).

�Amplifier with gain of 10 to 1000 are used to increase these

signals to levels of 1 to 10 V that are compatible with the

voltage measuring devices.

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

3.4

Am

plifi

ers

: 3.

4 A

mpl

ifier

s :

16

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

�Are voltage measuring devices used to display the measurement in a

form

that can be read and interpreted.

�Recorders may be analog or digital.

�The voltage from the amplifier is an analog signal that is the input to

the recorder.

�Analog recorders such as oscilloscopes, oscillographs and magnetic

tape recorders display or store the analog signal.

�Digital recorders accept the analog signal and convert it to a digital

code that is displayed in a numerical array, or stored on magnetic

media.3.T

he E

lect

roni

c In

stru

men

t Sys

tem

3.5

Rec

orde

rs :

3.5

Rec

orde

rs :

17

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

�The data processor are generally micro-computers that accept the

digital input and perform

computations in accordance with

programmed instructions.

�The output is displayed in graphs and tables.

�Data processors are only used when the instrument system

incorporates analog-to-digital converter (A/D) and provides the

output signal representing the measurement in a digital code.

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

3.6

Dat

a P

roce

ssor

: 3.

6 D

ata

Pro

cess

or :

18

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

�It is a device that provides a control voltage that represents the

variation (usually with respect to time) of an important parameter in

a given process.

�Example: the time-temperature profile for an oven must be

controlled in curing plastics.

�The command generator provides a voltage signal that varies with

time in exact proportion to the time-temperature profile required of

the curing oven.

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

3.7

The

com

man

d G

ener

ator

: 3.

7 T

he c

omm

and

Gen

erat

or :

19

Dr.

Kar

im B

ouro

uni,

EN

IT 1

A G

M, C

ours

e of

Mea

sure

men

t and

Inst

rum

enta

tion

�Are used to monitor and adjust Any quantity that must be

maintained at a specified value to produce a material or productin a

controlled process.

�The signal from the instrumentation system is compared with a

command signal that reflects the required value of the quantity in the

process.

�The process controller accepts both the command signal and the

measured signal and form

s the difference to give an error signal.

�The error signal is then used to automatically adjust the process.

3.T

he E

lect

roni

c In

stru

men

t Sys

tem

3.8

Pro

cess

Con

trol

lers

: 3.

8 P

roce

ss C

ontr

olle

rs :

20