skee2133 05 chapter 1 metrology

7/29/2019 SKEE2133 05 Chapter 1 Metrology

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Dr.Leow PeiLing

FacultyofElectricalEngineering

Universiti Teknologi Malaysia

81310UTMSkudai,Johor

Malaysia

Email:[email protected]

Mobile:0167617853

Office:P19a,Level5,Room050211

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IntroductionIntroduction

Metrology definition:Metrology definition:

1. International Bureau of Weights and Measures (BIPM)

the science of measurement, embracing both experiment

and theoretical determinations at an level of uncertaint in

any field of Science and Technology.

2. International Organization of Legal Metrology (OIML)

Science of Measurement that concerns units, instruments &

method performed by competent bodies.

3. Generally defined as Science of Measurement.

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IntroductionIntroduction

Metrology may be divided into 3 subfields:

Scientif ic or fundamental metrologyconcerns the establishment of measurement units, new measurement

me o s, measuremen s an ar s an e rans er o racea yidentification from these standards to users in society.

Applied or industrial metrologyconcerns the a lication of measurement science to manufacturin

suitability of measurement instruments, calibration and quality control of

measurements.

Legal metrology

of health, public safety, the environment, enabling taxation & consumers


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*Traceability-the ability to verify the history, location, or application of an item by means of recorded

TerminologyTerminology

agreement between a test result

& acce ted reference value

Precision the closeness with arepeated set of measurements of

the same variable a rees with the

average of the set of

measurements

Bias the difference between the

expectation of the test result & an

accepted reference value


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Fill u theFill u the

targettarget

thelabelsthelabels


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Calibration the process of

indication on a measurement

value of the applied

,

accuracy

Measurement set of operations having the object of

determining a value of a quantity


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product, process or service to the standard (i.e ISO, HALAL etc.)


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Metrolo ical confirmation a set of o erations re uired to

ensure that measuring equip. complied the requirement.

Correction - is an action to rectify, compensates for

uncorrected result of measurement.

Drift a slow change of a metrological characteristic of instr.


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TerminologyTerminology(thestudyoftermsandtheiruse)(thestudyoftermsandtheiruse)

Reproducibility The closeness of agreement between

measurement of the same quantity carried out with a stated

change in conditions. The ability of a test or experiment to beaccurately reproduced, orreplicated, by someone else

working independently.

Result by Alice Result by Abu


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variable to which and instrument will respond


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ncer a n y ac o cer a n y, range o va ues w n w c

the true value of a measurand lies.

Certaint vs uncertaint


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nspec on nvo ves measuremen , nves ga on, es ng n

order to fulfilled requirement

Quality relates to all characteristic that meet

reference

Verification investigation that specified requirements

fulfilled


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DerivedUnitsDerivedUnits

Derivedquantity SIderived unit

name

Symbol InSI

units

InSIbaseunits

Frequency Hertz Hz s1

Force Newton N mkgs2

Pressure,stress Pascal Pa Nm2 m1kg s2

Energy,work,quantityof Joule J Nm m2kg s2

heat

Power,radiantflux Watt W J/s m2kg s3

Electriccharge,quantity

ofelectricity

Coulomb C s A

ec r cpo en a

difference,emf

o m g s

Electricca acitance farad F C V m2k 1s4 A2

Electricresistance ohm V/A m2kg s3 A2

Electric conductance Siemens S A V m2k 1 s3 A2


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DerivedUnitsDerivedUnits

Derivedquantity SIderived unit

name

Symbol InSI

units

InSIbaseunits

Magnetic ux We er W VS m g s A

Magneticinduction, tesla T Wb/m2 kg s2 A1

Inductance Henry H Wb/A m2kg s2 A2

Luminous flux Lumen lm Cd sr m2m2 cd=cd

illuminance Lux lx Lm/m2 m2m4 cd=m2 cd

Radioactivit ofa bec uerel B s1

radionuclide)

Absorbed dose,kerma, gray Gy J/kg m2s2

specificenergy

Doseequivalent Sievert Sv J/kg m2s2

aneang e a an ra m m =

Solidangle Steradian sr m2m2 =1


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SupplementaryUnitsSupplementaryUnits

Unit that is outside of SI but accepted

Quantity Unit Symbol ValueinSIunits

,

,

day ,

,

1h=60min=3600s

1day=24h=1440min=

86400s

Planeangle Degree,minute, gon 1 =(/180)rad

= =,

1 =(1/60)(/648000)rad

1gon =(/200)rad ;

Volume litre l,L 1l=1dm3 =103 m3

Pressureinair,fluid bar bar 1bar=105Pa


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PrefixPrefixSI Prefix (for decimal multiple or submultiple - exponent

10n Prefix S m Shortscale Lon scale Decimale uivalent

1024 yotta Y septillion Quadrillion 1000000 000 000 000

000 000 000

1021 zetta Z sextillion Trilliard (thousand

trillion)

1000000 000 000 000

000 000exa u n on r on

000

1015 eta P uadrillion Billiard thousand 1000000 000 000 000

billion)

1012 tera T Trillion Billion 1000000 000 000

109 giga G Billion Milliard(thousand

million)

1000000 000

mega on

103 kilo k Thousand 1000


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ec o un re

101 deca da Ten 10


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DimensionDimension

Dimension of Physical Quantities

Uses symbol M (mass), L (length), T (time) known as mech.

-, ,

Exam le 1

- Dimension of physical quantity SPEED is L/T (or in

units m/s km/h m h

QUANTITY UNIT DIMENSION

SPEED m/s L/T


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DimensionDimension Dimensionofaphysicalquantityisthetotalof

.

Forexample,speedisgivenasdistancextime;metres/second(m/s)MKSand

centimetres/second(cm/s)inCGSsystem.

Dimensionofmeasurementofspeed,

v =


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DimensionDimension

Dimension of Ph sical Quantities

Example 2;

Velocity = length/time

[v] = [L]/[T] = [LT-1]

Acceleration = velocity/time

[a] = [v]/[T] = [LT-1]/[T1] = [LT-2]

Force = mass acceleration

= - = -


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DimensionDimensionDimensional Consistency

Dimensions and units must be handled consistently in any

al ebraic calculation. Two uantities must have the same

dimensions and units.


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DimensionEqua.DimensionEqua. E.S.UDim.E.S.UDim.

. .

b Current

[I] = [Q]/[T] = [1/2M1/2L3/2T-1]/[T]

I = 1/2M1/2L3/2T-2

c) e.m.f. (electromotive force) or potential difference

[E] = [W]/[Q]

[E] = [ML2T-2]/[1/2M1/2L3/2T-1]

[E] = [-1/2

M1/2

L1/2

T-1

]

W = work (Joule)


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DimensionEqua.

Dimension

Equa.

E.S.U

Dim.E.S.UDim.

. .

d Ca acitance C

C = Q / E

C = Q / E = 1/2M1/2L3/2T-1 / -1/2M1/2L1/2T-1

[C] = [L]

e) Resistance, R

[R] = [E]/ [ I ]

[R] = [-1/2M1/2L1/2T-1] / [1/2M1/2L3/2T-2]

[R] = [-1L-1T]


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DimensionEqua.DimensionEqua. E.M.UDim.E.M.UDim.

b) Magnetic force, H

][][][

][ 12/12/12/112/32/12/1

2

=== TLM

TLM

MLT

m

FH

c) Current d) Charge

2=

IH

timecurrentCharge =

][][ 12/12/12/1 =

ITLM

r

]][[][

12/12/12/1TIQ

=

][][ 12/12/12/1 = TLMI ][][2/12/12/1

LMQ=


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DimensionEqua.

Dimension

Equa.

E.M.U

Dim.E.M.UDim.

. .

e Potential volta e / Potential difference

Potential voltage = work/charge

][][

][

][

][][ 22/32/12/1

2/12/12/1

=== TLMLM

TML

Q

WE

f) Capacitance, C

][][

QC =

][][

][ 2112/12/12/1

TLLM

C

==


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MKSUnitSystemMKSUnitSystem urren

[I] = [-1/2M1/2L1/2T-1]

MKS unit for current/ C.G.S. unit for current

1

12/12/12/17

1011100100010

=

MKS current unit = 10-1 C.G.S. current unit = 1 A

c) Emf

= 1/2 1/2 3/2 -2

MKS unit for emf / C.G.S. unit got e.m.f =

8

12/32/12/17

1011

1

1

100

1

1000

1

10=


45MKS emf unit = 108 C.G.S. Emf unit = 1 G volt

MKSUnit

SystemMKS

Unit

System

d) Resistance, R-

. . .

9

17

101110010 =

MKS resistance unit= 109 C.G.S. resistance unit = 10 G

e) Inductance, L

MKS unit for inductance / C.G.S. unit for inductance9

7

1011

100

1

10=


MKS inductance unit = 109 C.G.S. inductance unit = 10 GH


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MKSUnitSystemMKSUnitSystem

f) Capacitance, C

= -1 -1 2

MKS unit for capacitance / C.G.S. unit for capacitance =

9

2117

1011

1

1

100

1

10

=

MKS capacitance unit = 10-9 C.G.S. capacitance unit = 10 nF


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PracticalUnitPracticalUnit

No Quantity Practical Symbol Noofe.m.C.G.S. unitin Definition

Unit onepracticalunit

1 Charge Coulumb Q 101

Q =It

urrent mpere

3 Voltage Volt E 108 E =IRes s ance m

5 Inductance Henry L 109 E=Ldl/dt =

7 Power Watt P 1 Watt=107 energy/sec

7

1kWh=3.6 103 erg


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MKSUnitSystemMKSUnitSystem

Example

While solving for Hay Bridge

22CRRR

2

2

2

1

21 RCx

+=

In E.M.U dimension,

R, R1, R2, R3 = [LT-1]

C = [-1L-1T2] =[T-1]


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MKSUnit

SystemMKS

Unit

System

Example (cont.)

analyse the equation using dimensional analysis

22212

1321

1 RC

CRRRR x

+=

][][][][[][ 2211111211

TLLTLTLTT

][][][1

422312

21221121+

LTTLT

]][][[1 2224222+=

TLTLT

11 +=

LT


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whichallhavestateduncertainties.Thisensuresthata

measurementresultorthevalueofastandardisrelatedto

referencesatthehigherlevels,endingattheprimary

standard.

Anendusermayobtaintraceabilitytothehighest

international level either directl from a National Metrolo

Instituteorfrom secondarycalibrationlaboratory.

,

traceabilitymaybebeobtainedfromlaboratoriesoutsidethe


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TheTraceability

ChainThe

Traceability

Chain


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TraceabilityTraceability CalibrationCalibration

Traceability is a characteristic of a calibration or ameasurement. A basic tool in ensuring the traceability of ameasurement is the calibration of a measuring instrument or

.characteristics of an instrument or reference material. It isachieved by means of a direct comparison againstmeasurement stan ar s or certi ie re erence materia s.Acalibration certificate is issued and in most cases, a sticker is

Threemainreasonsforhavinganinstrumentcalibrated:

. oensurerea ngs romt e nstrumentarecons stentw t ot er

measurements.2. Todeterminetheaccuracyoftheinstrumentreadings.

3. Toestablishthereliabilityoftheinstrumenti.e.thatitcanbetrusted.


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TraceabilityTraceability

a ona e ro ogy ns u e, san ns u e es gna e

bynational

decision

to

develop

and

maintain

national

.

Somecountriesoperateacentralisedmetrologyorganisation

w one . e may evo ve ema n enanceo

specificstandardstocertainlaboratorieswithoutthesehaving

.

organisationwithamultiplicityofinstitutes,allhavingthe

.


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TheRoleofMetrologicalInstitutions

Theworldeconomyandthequalityofoureverydaylifedependon

reliable measurementsandtestswhicharetrusted andaccepted

internationallyandwhichdonotformabarriertotrade.

Inadditiontothoseregulationsrequiringlegallyverified

instruments,manyregulatedareasrequiremeasurementsand

testingtoassesscompliance,eitherwiththeregulationsor

. . , ,

environmentalandpollutioncontrolandthesafetyofchildrensto s.Data ualit measurementsandtestin areanim ortant art

ofmanyregulations.


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NationalMetrologyInstitutesandotherorganisationsprovide

adviceandguidanceonmeasurementissuestotheusers.

Regulatoryguidetobestmeasurement,practiseMeasurementmay

berequiredatanystageduringtheregulatoryprocess. Goodregulationsrequireanappropriateapproachto

measurement/testingwhen

Establishingtherationaleforlegislation

Writingtheregulationandestablishingthetechnicallimits

undertakingmarketsurveillance


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Accreditedlaboratories

Accreditationisathirdpartyrecognitionofalaboratorystechnicalcompetence,qualitysystemandimpartiality.Publicaswellasprivate

laboratoriescanbeaccredited.Accreditationisvoluntary,butanumberofinternational,Europeanandnationalauthoritiesassurethequalityoftestingandcalibrationlaboratorieswithintheirareaofcompetencebyrequiringaccreditationbyanaccreditationbody.

Insomecountries,forexample,accreditationisrequiredforlaboratories

stores.Accreditationisgrantedonthebasisoflaboratoryassessmentandregularsurveillance.

, . .

ISO/IEC17025Generalrequirementsforthecompetenceoftestingandcalibrationlaboratories,andtechnicalspecificationsandguidelinesrelevantor e n v ua a ora ory.


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Designatednationallaboratories

DesignatedlaboratoriesinmostcountriesarenominatedbytheNMIin

fieldsandinaccordancewiththemetrologicalpolicyofthecountry

Therefore accreditation bodies have internationall and re ionall a reed

multilaterial agreementsofeachotherssystemsandofcertificatedand

testreportsissuedbytheorganisationsaccredited.

skee2133 05 chapter 1 metrology

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