2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 1 Development of Complex Curricula for Molecular Bionics and Infobionics Programs within a consortial* framework** Consortium leader PETER PAZMANY CATHOLIC UNIVERSITY Consortium members SEMMELWEIS UNIVERSITY, DIALOG CAMPUS PUBLISHER The Project has been realised with the support of the European Union and has been co-financed by the European Social Fund *** **Molekuláris bionika és Infobionika Szakok tananyagának komplex fejlesztése konzorciumi keretben ***A projekt az Európai Unió támogatásával, az Európai Szociális Alap társfinanszírozásával valósul meg. PETER PAZMANY CATHOLIC UNIVERSITY SEMMELWEIS UNIVERSITY sote_logo.jpg dk_fejlec.gif INFOBLOKK 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 2 Peter Pazmany Catholic University Faculty of Information Technology ELECTRICAL MEASUREMENTS Introduction and principles of measurement www.itk.ppke.hu (Elektronikai alapmérések) Bevezetés és a méréstechnika alapelvei Dr. Oláh András 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 3 Electrical measurements: Introduction and principles of measurement Outline • Measurement in everyday life • Pillars of the information technologies • Course information • History of measurements • Trends in measurement technology • Fundamentals and principles • Modeling and measurements methods • Structure of measuring systems • The computermeasuring systems(Labview) 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 4 Measurement in everyday life • Measurementofordinarypeopleforeveryday– “Itiscoldtoday”:itdescribestheresultofmeasurementcarriedoutbyoursenses(receptors).Suchmeasurementisperformedinasubjectiveway-anotherpersoncouldstateinthesameconditionsthatitisnotcold.Butgenerallyweestimatethetemperaturebycomparisonwiththetemperaturememorizedasareferenceone.Thusweperformedthemeasurement. – “Idonotfeelwelltoday”:itdescribestheresultoftheanalysisofthestateofourorganism.Ourreceptorstestedtheparameters:bloodpressure,bodytemperature,pulseheartrate,levelofadrenalineinblood,etc.asincorrect.Thereceptors(thesensors)determinethevalueofmanyquantitieswhicharetransmittedtothebrain(centralcomputer)astheelectricalsignals(currentisabout100pA)bytheinterfaceconsistingofbillionsofnervousfibers. Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 5 Measurement in everyday life(cont’) • Goalofmeasurement:measurementistheprocessofgathering • Informationfromphysicalworld. • Intuitivedefinition:measurementisestimationofthequantityofcertainvalue(withknownuncertainty)bycomparisonwiththestandardunit. • Practicallyalmostthewholeactivityofourlivesisrelatedtomeasurementswe:– constantlycomparevariousobjects – evaluatetheirproperties – determinetheirquantities. Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 6 Measurement in everyday life: an example • Examples:– Whilepayingincashatthesupermarket. – Whilelisteningtoourfavoritebandattherockconcert. – Whilechoosingthecolorofthewallsbeforepainting. • Fundamentalsofcolourvision:– Physicalcolour=specificwavelengthsofradiation(combinationofpurespectralcoloursinthevisiblerange) – Psychophysicalcolour=Chromaticity=Toachieveastandard,sharedtechnicaldescriptionoftheperceptualeffectsoflightstimulionhumanobservers,internationalorganizationshavedevelopeda"standardobserver".Thisisahypotheticaltypicalhumanvisualsystemthatisdescribedintermsofequationsrelatingitsquantitativevisualresponsestomeasurablephysicalstatisticsoflightstimuli.Thedescriptionsaretherefore"psychophysical". Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 7 Measurement in everyday life: an example (cont’) Electrical measurements: Introduction and principles of measurement Photometric quantities Eyes Opticnerves Brain- Visual cortex Optical lens Optical filter Optical sensor Optical lens Optical sensor 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 8 • Colour:itisthevisualperceptualpropertycorrespondinginhumanstothecategoriescalledred,green,blueandothers. • Colourfulness:itisthedifferencebetweenacolouragainstgray(eg.:grayishpink) • Lightness:isapropertyofacolour,oradimensionofacolourspace,thatisdefinedinawaytoreflectthesubjectivebrightnessperceptionofacolourforhumansalongalightness–darknessaxis. Electrical measurements: Introduction and principles of measurement Eye sensitivity diagram. The colored vertical lines are the wavelengths of some common laser colours. The yellow line is the 589nm sodium line. Measurement in everyday life: an example (cont’) http://en.wikipedia.org/wiki/File:Eyesensitivity.png 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 9 Measurement in everyday life: an example(cont’) Electrical measurements: Introduction and principles of measurement Fájl:PlanckianLocus.png chromaticityspace(CIE) C:\Documents and Settings\OlahAndras\Local Settings\Temporary Internet Files\Content.IE5\1QLK7RXU\MCj02812840000[1].wmf Comparativecolourmeasurement(subjective) Unknown light source Known light source prism 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 10 Pillars of the information technologies • Technology:electronic,optic,magnetic,algorithmic,…..technologiesadvancedproducts,suchasbuildingblocks(e.g.:processor,opticalcable,magneticstorage,FastFourierTransformation,etc.…)andtheblocksformcomplexsystems(e.g.:computers,communicationnetworks,serverfarms,etc.…) • Informationsources:informationisgeneratedandutilizedbyITtools(e.g.:speeches,images,papers,books,films,music,financialtransactions,etc.…) Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 11 Pillars of the information technologies(cont’) • Interfaces:amongphysicalanddigitalworldsEe.g.:sensors,ManMachineCommunicationinterfaces,etc.) • Signalporcessing:signalprocessingandevaluationbymachineintelligence • Infocommunications:informationtransfer,communication,preprocessingandpresentation.(e.g.:GSM,broadcasting,speechsynthesis,etc.…) Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 12 Whichpillaris more importantthantheother? Electrical measurements: Introduction and principles of measurement rockpaperma6 Technologies Information source Interfaces Signal processing Infocommunications http://en.wikipedia.org/wiki/File:Rock_paper_scissors.jpg 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 13 Featuresof a succsessfulcomputer-engineer • He/sheshouldpossessadeepknowledgeinhis/herfieldofactivity(q.v.pillarofinformationtechnology) • He/sheshouldbereceptiveto(all)newscientificachievementsorproductsandalsotoalteredopinionsbutalsoshouldstaycriticalevaluatingthem. • Anexcellent/thefavourablecomputer-engineerworksinteam.He/sheiscompetentnotonlyinhis/herownfieldofactivitiybutalsointheotherteammembers’.Anengineerissupposedtohaveasubstantiveopinioninconsultationsandtoargueinemergingdiscussions. • Afundamentaltool/sourceofknowledgeinscienceismakingexperiments(performingmeasurements)andtakingdecisionsinsubstantivearguementsoftechnologicalfieldisinmostcasesmeasurement-based. Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 14 Whatis measurementtechniquesusedfor… …inthemolecularbionicsfaculty? …inclinicalpractice? Electrical measurements: Introduction and principles of measurement P1010010a N. Szigeti-CsucsMD. everyday routine of a Hungarian clinician 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 15 The (fundamental) roleof thecourseElectricmeasurementsintrainingcomputer engineersatPPKU • Acquiringpillarsofknowledgeishardnotonlybecauseofcomnplexitybutalsobecauseworkingprinciplesofbuildingblocksisnotalwayseasilysensible • Measurementcanmakeprocessessensiblewhichhelpsunderstandingtheworkingprinciplesbeforedeepunderstandingoftechnical • Don’tbeafraid!Everyonewillandshouldgetusedtotheregime,theproceduretherequireddisciplinebeforestartingworkinmajorcourses. • Electricalmeasurementcanaimatbeautyofourprofession,whichhelptounderstandandacceptthehardworkwhileattendingtheinitialcoursesofcomputerengineering. Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 16 Whatdoeselectricalmeasurementstandsfor? • Principlesandbasicsofelectricalmeasurement • Essentialelectronicalknowledge • Obtainingaprimaryroutineinperformingmeasurements • Measuringelementaryelectricalquantities • Fundamentsofmeasuringnon-electricalquantities(time,distance,geographicallocation) • Elucidationofsomebasicproblemsinsignalprocessingandcircuittheory • Structureofbasicmeasurementdevices(uniquegeneralinstruments,devicesconnectedtothecomputer,measurementsutilizingacomputer,virtualinstruments) • Medicalelectronicalmeasuremnents,measurementofbiologicalsignals Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 17 Course Syllabusand Scheduling 1. Introduction and principlesof measurement(Chapter1)– Focusofthecourseandprerequisites – Historyofmeasurements – Fundamentalsandprinciples – Modellingandmeasurementmethods – Structureofmeasuringsystems,comptermeasuringsystems 2. Uncertainty of measurements (Chapter2)– Basicstatisticaltermsandconcepts – Interpretationofuncertainty 3. Measurement of voltage and time(Chapter3)– Measurementofvoltageandcurrent – Measurementoffrequencyandtime – TheELVISsystem Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 18 Course Syllabusand Scheduling(cont’) 4. Fundamentals of signal processing(Chapter4)– Aboutthedecibel – AnalogtoDigitalconversion(sampling,quantization) – Signaltransformation – Theconceptofnoise 5. Positioning systems (Chapter5)– Positioningandlocalizationmethods – Sattelitebasedpositioningsystems(GPS) 6. Theoretical approach to networks and system(Chapter6)– Kirchhoffcircuitlaws – Networkandsystemanalysis – Linearresistiveanddynamicnetworks Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 19 Course Syllabusand Scheduling(cont’) 7. Semiconductors basics: diodes and transistors(Chapter7)– circuitmodel,characteristicsandapplications ›Midtermexam 8. Nonlinear resistive networks (Chapter8)– settingoftheoperationpoint 9. Logic system(Chapter9)– binarysystemandbasicoperation 10. Basics of microcontrollers (Chapter10)– Complexlogicproblems – Fundamentals(structureandprogramming)ofmicrocontroller Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 20 Course Syllabusand Scheduling(cont’) 11. Biological and medical measurements (Chapter11) ›Finalexam MeasurmentLab(Chapter12) – Labview(3x3) – ELVIS(2x3) – GPS(1x3) – Diode(1x3) – Transistor(1x3) – Microcontroller(1x3) – Medicalmeasurements:bloodpressure,respiration(2x3) Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 21 Course Information Requisite: • To pass thephysicstest; • To complete each measurement task of the lab– Howtopreparefora measurementtask? Withthehelpof theinstructionsforthegivenmeasurementand withuseof therelatedcurriculum (??) knowledge. Thisletteris tobe checkedbymini tests. – Missedmeasurement(s) canbe fulfilledonthedisposedextra lab(onlyonce) • Test gradesshouldbe atleast • Grading– Practical grade:roundedgradesfromthetestsbeforethemeasurementsand thegradereceivedforthemeasurementreports – Final grade: Round (1/2 x (1. Exam grade + 2. Exam grade ) + 1/2 x practical grade) Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 22 Requirementsof measurementreports • Shouldinclude– Placeand dateof measurement, namesofthemeasuringteam – The titleof themeasurement, thelistoftheinstruments/devicesapplied, theshemeofthemeasurementprocedureifneeded – Resultsof themeasurement(indicatingtheunit of thequantity!!) – Evaluationand interpretationof themeasurementresults • Measurementreportshouldbe writteninelectronicformand shlouldbe sentase-mail attachementtotheadressalwaysgiveninthesyllabusof themeasurementtask. Subjectis alsogiveninthedescription. Shouldbe sentnotlaterthenmidnightof thedayofmeasurement • Copyingorborrowingpartsof othersmeasurementresultswilllead toa disciplinaryprocedure Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 23 •Fromtheverybeginningofourcivilizationpeopletriedtounderstandandcomprehendthesurroundingworld. • ArtofmeasurementsappearedinEgypt. • ScienceofmeasurementsapperaedbyGreeks. • Theancientwonderswerenotonlydesigned,butaccuratemeasurementswereneededtoimplementthem. Electrical measurements: Introduction and principles of measurement History of measurements: the ancient wonders http://en.wikipedia.org/wiki/File:SevenWondersOfTheWorld.png 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 24 Electrical measurements: Introduction and principles of measurement http://en.wikipedia.org/wiki/Pont_du_gard History of measurements: the ancient Roman aqueduct • Roman aqueducts were extremely sophisticated constructions. • Pont du gard(year19 BC)– It is a 50 km long aqueduct that runs between Uzesand Nîmes. – Itwasbuilt withremarkably fine tolerances, and of a technological standard that had a gradient of only 34cm per km (3.4:10000), descending only 17 m vertically in its entire length of 50 km. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 25 Electrical measurements: Introduction and principles of measurement History of measurements: story of the chronometer • ThefirstEuropeanvoyagesofdiscovery,havemadeitincreasinglyimportantforships'captainstobeabletocalculatetheirpositionaccuratelyinanyoftheworld'sseas.Withthehelpofthesimpleandancientastrolabe,thestarswillreveallatitude.Butonarevolvingplanet,longitudeisharder.Youneedtoknowwhattimeitis,beforeyoucandiscoverwhatplaceitis. • Mainstagesoftimemeasurement:– Sundialandwaterclock(fromthe2ndmillenniumBC) – Hero'sdioptra(1stcenturyAD) – Thehour(14thcenturyAD) – Minutesandseconds(14th-16thcenturyAD) – Barometer(AD1643-1646) – Mercurythermometer(AD1714-1742) – Chronometer(AD1714-1766) – Sextant(AD1731-1757) 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 26 Electrical measurements: Introduction and principles of measurement SirClowdisleyislostinafogintheEnglishChannel.Hegathersthenavigatorsofhisfleettogetadefinitefixontheirlocation.SatisfiedthattheyaresafelyoffthecoastofFrance,heordersacoursehome.Whenasailortriestowarnhimthathe'sindangerofwreckingontheScillyIsles,theadmiralordersthemanhangedasamutineer.Hourslater,hisflagshipandthreeothershipsofhisfleetsmashintotherocks.Heissweptashoreonlytobemurderedbyawomanwhowantedhisemeraldring. History of measurements: story of the chronometer (cont’) http://en.wikipedia.org/wiki/File:Sir_Cloudesley_Shovell,_1650-1707.jpg j0303494 Sir Cloudesley Shovell (1650-1707) Toulon Isles of Scilly 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 27 Electrical measurements: Introduction and principles of measurement TheBritishgovernment,in1714,setsupaBoardofLongitudeandoffersamassiveL20,000prizetoanyinventorwhocanproduceaclockcapableofkeepingaccuratetimeatsea. TowintheprizeachronometermustbesufficientlyaccuratetoloseorgainnotmorethanthreesecondsadayalevelofaccuracyunmatchedatthistimebythebestclocksinthecalmestLondondrawingrooms. ThechallengeappealstoJohnHarrison.Itisnearlyfiftyyearsbeforehewinsthemoney. History of measurements: story of the chronometer (cont’) John Harrison (1693-1776) http://en.wikipedia.org/wiki/File:Harrison%27s_Chronometer_H5.JPG http://en.wikipedia.org/wiki/File:John_Harrison_Uhrmacher.jpg 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 28 Electrical measurements: Introduction and principles of measurement History of measurements: Budapest (1980) 18 19 • Itwasbuiltin1980,Budapest • Constructor:PeterWellner,civilengineerHídépítõCo.RecentlyknownasHídépítõZrt.1 • Thelegends:– Thecauseofthefailureisthatadifferentpointofreferencewasusedwhilemeasuringelevationlevel(thereisadifferenceasmuchas0.675mbetweenelevationmeasuredwithanAdrianandBalticzeropoint – Oneendoftheoverpasssubsidesmorethantheotherbecausebuildingmaterialswerestolenfrombothparts,butnotthesameextent 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 29 History of measurements: Budapest (1980) (cont’) • Infact:– „Whenpositioning,spanningandspuddingsteelcablesitbehaveslikearubbercablefirstbentthenreleased:thecablewouldcompressiflet.Thisfeaturewillgainpressurewhichisusedforload-bearing.Ifalargeforceisloadedonthebridgebeforethejointingmaterialcansolidify,thenthepartsexpandatthebottomandangletopwards.” – Theywereordered(bythemanagementofthecity)tohurryupwiththeworksastramserviceshouldberestored.Thisleadtotheresult,thatthecontractorshaveputthepartstogethernotwaitingforthejointingmaterialtosolidify” Electrical measurements: Introduction and principles of measurement 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 30 Electrical measurements: Introduction and principles of measurement TheMarsClimateOrbiterwasintendedtoenterorbitatanaltitudeof140.5–150km(460,000-500,000ft)aboveMars.However,anavigationerrorcausedthespacecrafttoreachaslowas57km(190,000ft.) Thespacecraftwasdestroyedbyatmosphericstressesandfrictionatthislowaltitude.ThenavigationerrorarosebecauseLockheedMartin,thecontractorsforthecraft'sthrusters,didnotuseSIunitstoexpresstheirperformance History of measurements: NASA spacecraft http://en.wikipedia.org/wiki/File:Mars_Climate_Orbiter_2.jpg Mars Climate Orbiter ~125 millió $ 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 31 Electrical measurements: Introduction and principles of measurement The concept of the measurement and measuring • Measurement= obtaining information about the state of the process – physical , chemical, biological, economical, social phenomenon • Measuring = methods and tools Transducer Signal processor Physical phenomenon x(t) Sensor y(t) Clear and known relationship z(t) Essential features FEATURE EXTRACTION Electrical signal Computer›processing + storage 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 32 Electrical measurements: Introduction and principles of measurement Applicationof measurementtechniques Measuring Techniques Production Research Metrology Quality Assurance Develop- ments Main- tenance Measuring Techniques Transport Services Production Envi- ronment Trade Health 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 33 Electrical measurements: Introduction and principles of measurement Traditionalmeasuringsystem • Most of themdid not have output interfaces. • Each instrument enabled the measurement of different signals. • A typical researcher was surrounded by many instruments. • Theexperimentrequired the activity and presence of a researcher. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 34 Electrical measurements: Introduction and principles of measurement Measuring system Bosch Automotive Sensors 2002 Recentlythemeasuringtechniqueschangedsignificantly. real revolution in measurements Informatics Microelectronics Mechatronics Sensor technology Interface systems Signal processing techniques Digital signal processors Virtual instruments Widespread of computer systems Today, dozens of various sensors are installed in any new car 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 35 Electrical measurements: Introduction and principles of measurement Computer measuringsystem LabVIEW–National Instruments TestPoint–Capital EquipmentCorp. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 36 Electrical measurements: Introduction and principles of measurement WSN based measuring system Electrical measurements: Introduction and principles of measurement •Processing unit– Microprocessor – Microcontroller • Transceiver unit– Short range radio • Sensing unit– Sensors – Actuators – Location finding system • Power supply subsystem– Battery – DC-DC converter System architecture of a canonical wireless sensor node ~20% ~50% ~30% Electrical measurements: Introduction and principles of measurement •TheBell’slawdescribeshowcomputerclassesform,evolveandmayeventuallydieout.Newclassescreatenewapplicationsresultinginnewmarketsandnewindustries. • Anewclassformsabouteverydecade:– mainframes(1960s) – minicomputers(1970s) – personalcomputersevolvingintoanetworkenabledbyLANorEthernet(1980s) – webbrowserclient-serverstructuresenabledbytheInternet(1990s) – webservices(2000s) – smallform-factordevicessuchascellphonesandothercellphonesizeddevices(2000) – WirelessSensorNetworks(>2005) • Homeandbodyareanetworkswillformby2010 Wireless sensor networks (outlook) Gordon Bell (1934-) Electrical measurements: Introduction and principles of measurement Wirelesssensornetworks(outlook) • Manycheapnodes– Wireless›easytoinstall – Intelligent›collaborationandcooperation – Low-power›longlifetime • Wirelessnetworkscharacteristics– Energyisthedrivingconstraint – Dataflowstocentralizedlocation – Lowper-noderatesbuttenstothousandsofnodes – Intelligenceisinthenetworkratherthaninthedevices Electrical measurements: Introduction and principles of measurement Wireless Sensor Networks: envisioned applications • Smarthomes/buildings • Smartstructures • Searchandrescue • Homelandsecurity • Battlefieldsurveillance • Eventdetection • Agriculture • Medical Agriculture Urban Warfare Fire Fighting Medical Process Industry AND MANY MORE…. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 41 Electrical measurements: Introduction and principles of measurement Main trends in the measurementsscience • Replacinganalogdeviceswithdigitaldevices • Automatedcomputerbasedmeasuringsystemsinsteadofoperatorcenteredtraditionalmeasuringsystems.– „userfriendly”softwareenablingthedesigntobemadedirectlybyend-usersofthemeasuringinstrumentsandeventhewholemeasuringsystems.Thesesoftwaresmostlyhavesimplegraphicalprogramminglanguage.ThemostpopularsoftwareofsuchtypeisLabVIEWproposedbyNational. – Becausethemeasuringdeviceisinsidethecomputeritisoftencalledasa“virtualinstrument”. • Globalizationofmeasurementscienceandtechniques:measurementsareperformedbyalmosteveryone(physicists,medicaldoctors,engineers,farmers,etc.).Itisavailableforeveryonetomeasurewithbetterorworseresults. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 42 Electrical measurements: Introduction and principles of measurement What is the role of engineering knowledge? • Specialistsarestillneeded,since:– Ifweuseincorrectmodelormethods,thenonecanusuallyobtaincompletelyfalseresult(eg.:theresearcherwasinvestigatinganinsect). – Suchgoodperformancesmayleadtomisunderstanding. – Analysisofthemeasuringaccuracy(crucialforcorrectmeasurements). • Interdisciplinarity:– Digitalsignalprocessing. – Microcomputerapplications. – Microelectronicsandnanotechnology. – Signalanalysisandtransmission. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 43 Electrical measurements: Introduction and principles of measurement Principles of measurements • Measurementequalstocomparison • Eachmeasurementhassomeuncertainty! • Themeasurementchangestheinvestigatedphenomenon!Fittingofthemeasurandandmeasurementsystem. • Calibrationandcertification. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 44 Electrical measurements: Introduction and principles of measurement Measurement = comparision • Goalofthemeasurement:determinationthevalueofthemeasuredquantitywithappropriateprecision. • Thetaskofthemeasurement:comparisionbetweenthemeasuredvalueandmeasurementstandard(etalon). • Theetalonisnotalwayspresent!Butitcanbeindirectlymeasuredbytheuseofameasuringinstrument(whichiscalibratedviatraceabilitychain). 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 45 Electrical measurements: Introduction and principles of measurement Systemof measurement • Differentsystemsofunitsarebasedondifferentchoicesofasetoffundamentalunits.Eg:Planckunits(asoneamongsystemsofnaturalunits)– Speedoflight(c),gravitationalconstant(G),Planckconstant(h),Boltzmannconstant(k),electricconstant(.0) http://en.wikipedia.org/wiki/Planck_units 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 46 Electrical measurements: Introduction and principles of measurement International System of Units (SI) • Metricsystem,Antoine-LaurentLavoisier– On1August1793:thedecimalmetreisadopted – On7April1795:thegramisadopted • 1948,The9thGeneralConferenceonWightsandMeasures(CGPM) • 1954,The10thCGPMdecidedthatinternationalsystemshouldbederivedfromsixbaseunits • 1960,The11thCGPMnamedthesystemtheInternationalSystemofUnits,abbreviatedSI • 1971,Theseventhbaseunit,themole,wasaddedbythe14thCGPM 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 47 Electrical measurements: Introduction and principles of measurement SI penetration SI_Brochure_Cover http://en.wikipedia.org/wiki/SI 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 48 Electrical measurements: Introduction and principles of measurement SI base units http://en.wikipedia.org/wiki/SI 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 49 Electrical measurements: Introduction and principles of measurement SI derive units http://en.wikipedia.org/wiki/SI 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 50 Electrical measurements: Introduction and principles of measurement Measurementstandards(oretalon)canbeaphysicalmeasure,measuringinstrument,referencematerialormeasuringsystemintendedtodefine,realize,conserveorreproduceaunitoroneormorevaluesofaquantitytoserveasareference. Forexample,theunitofthequantity'mass'isgivenitsphysicalformbyacylindricalpieceofmetalofonekilogram,whichrepresentstheinternationalstandard,andgaugeblocksrepresentcertainvaluesofthequantity'length'. Definitionof etalon http://en.wikipedia.org/wiki/File:Denmark’s_K48_Kilogram.jpg 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 51 Electrical measurements: Introduction and principles of measurement Traceability Traceabilityofmeasurementresultsonamaterialispivotaltotheuseofthismaterial.Indeed,theplanningofthemeasurementsrelatedtothecharacterizationofthematerialdependsonthestandardtowhichtraceabilityshouldbeestablishedandthemeansbywhichtraceabilitywillbeestablished.Tobeabletoestablishtraceabilityofavaluetoacertifiedvalueofastatedreferencematerial,allmeasurementresultsthatareusedfortheassignmentofthisvalue(anditsuncertainty)needtobetraceabletothisstatedreference.Threedifferentkindsoftraceabilitycanbeenvisaged: • traceabilitytotheinternationalsystemofunit(SI); • traceabilitytoamethod; • traceabilitytoanartefact(toastandard,toaparticularinstrument). 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 52 Electrical measurements: Introduction and principles of measurement Measurement traceability chain CIPM International Committee for Weights and Measures BIPM International Bureau of Weights and Measures National Metrology Institute National Metrology Institute User calibrator Working standards Secondary standards Primary National standard Defination of SI unit International prototypes Precision level/ Uncertainty 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 53 Electrical measurements: Introduction and principles of measurement Estimation of error = measurement uncertainty • Uncertaintyisaparameterthatcharacterisesthedispersionofvalues. • Example:Ifavalueofamessisgivanas(1.24±0.13)kg,theactualvalueisassertedasliketobesomewherebetween1.11kgand1.37kg.Theuncertaintyis0.13kgandwenotethatuncertainty,likestandarddeviation,isapositivequantity(anerrormaybepositiveornegative). • Weareunabletodeterminethetruevalueofthemeasuredquantity,becausethemeasurementisalwaysperformedwithsomeuncertainty.Therefore,wecanstatethatthemeasurementwithouttheestimationofthisuncertaintyisworthless. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 54 Electrical measurements: Introduction and principles of measurement Each measurement has some uncertainty! • ISO:„Guidetotheexpressionofuncertaintyinmeasurement”,1993. • Analysisofmeasurementuncertainty–Metrology • Theresultantuncertaintyofmeasurementcancompriseseveralcomponents:– corrections – randomuncertainty – uncertaintyrelatedtotheimperfectaccuracyofmeasuringdevicesandmethods – uncertaintyrelatedtonon-perfectmodelofinvestigatedphenomenon – mistakes(validationcouldbeeffective). 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 55 Electrical measurements: Introduction and principles of measurement Source of uncertainty • Type-Buncertainties(Systematicorsystemerrors)– Itwillgiveexactlythesameresults. – Thistypeofuncertaintiesmaybeevaluatedbycalibration, – Atypeofsystematicerrorsisinstrumenterror(calibrationneeded) – Theothertypeofsystematicerrorsismethodormodelerror(theinstrumentisnotsuitableorthemeasurementdisturbsthemeasurendobject) • TypeAuncertainties(randomerrors)– Displayerror – Changintheenvironmentofthemeasurement(temperature,voltageorpressurefluctuations) – Noise,externalinterference 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 56 Electrical measurements: Introduction and principles of measurement Type-Auncertainties • Whenwerepeatthemeasurement,wewillobtainadifferentvalue.Thereasonforthislackofperfectrepeatabilityisthattheinstrumentweuseorthemeasurend,orboth,willbeaffectedbyuncontollableandsmallchangesintheenvironmentorwithinthemeasurenditself.Suchchangesmaybedue,forexample,toelectricalinterference,mechanicalvibrationorchangesintemperature. • Errorsthatfluctuate,becauseofthevariabalityinourmeasurementsevenunderwhatweconsidertobethesameconditions,arecalledrandomerrors. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 57 Electrical measurements: Introduction and principles of measurement Type-Buncertainties • Duringanymeasurement,therewillprobablybeanerrorthatremainsconstantwhenthemeasurementisrepeatedundersameconditions.Anexampleofsuchanerrorisaconstantoffsetinameasuringinstrument. • Examplesofintentionalchangethatmayuncoverasystematicerror:– Exchangingoneinstrumentforanotherthatiscapableofthesameaccuraccyandpreferablymadebyadifferentmanufacturer. – Havingadifferentpersonperformthemeasurement. – Anestablishedmethodofmeasurementandanovelmethodthatpromiseshigheraccuraccymaygivediscrepantresults,whichwillbeinterpretedasrevealingasystematicerrorintheearliermethod. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 58 Electrical measurements: Introduction and principles of measurement Evaluation of uncertainties • TypeAuncertaintiesareevaluatedbystatisticalmethods– Thiskindofevaluationrequirescertainnumber(K)ofmeasurements. • TypeBuncertaintiesareevaluatedbynon-statisticalmethods– Itmaybedeterminedbylookingupspecificinformationaboutameasurandsuchasthatfoundincalibrationreportordatabook. • Wecanreducecostsofmeasuringprocedurebydecreasingtheuncertaintybutthereoccurestheriskthatthecostsofincorrectdecisionscanraisehigher,itcanevencauseadangeroussitutation.Itispossibletoestablishtheoptimalvalueofuncertainty. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 59 Electrical measurements: Introduction and principles of measurement Fitting of the measurandand measurement system • Itisnecessarytofittheinstrumenttothemeasurand. • Example:voltagemeasuringbyrealvoltmeter U=Ug R2 R1+R2 U’= Ug R2 R2+ R1+ R1 Rm R2 R1 R2 Ug U Ug R1 R2 U’ Rm 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 60 Electrical measurements: Introduction and principles of measurement Accuracyvs. precision • Avalueobtainedthroughmeasurementmayormaynotbeclosetotherealvalue.Insituationswherewebelievethatthemeasuredvalueisclosetotherealvalue,wesaythatthemeasuredvalueisaccurate. • Whenvaluesobtainedbyrepeatedmeasurementsofaparticularquantityexhibitlittlevariability,wesaythatthosevaluesareprecise. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 61 Electrical measurements: Introduction and principles of measurement Modelling • Model=itseekstorepresentempiricalobjects,phenomena,andphysicalprocessesinalogicalandobjectiveway(functional,physical,mathematical,etc....models). • Themodelischaracterizedbyitsgoodness?(oritserror). • Necessarymodel:itcannotbefurtherreducedbecauseoftheintolerableerror.itcannotreduced…? • Sufficientmodel:morecomplexmodelsleadtounnecessarycosts. • Measurementplanning=selectingtheoptimalmodel. 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 62 Electrical measurements: Introduction and principles of measurement Modelling (cont’) • Example:determiningthedistancebetweentheEarthandMoon.– 1.Model:Theorbispoint›thedistancebetweenthepoints! – 2.Model:Theorbisperfectsphere›distancebetweenthecentersofthespheres? • Example:themodelofresistance– 1.Model: – 2.Model: i R u=Ri i R L 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 63 Electrical measurements: Introduction and principles of measurement Main methodsof measurements • Directmeasurementmethod • Indirectmeasurementmethod • Differentialmeasurementmethod • Substitutionmeasurementmethod • Analogueanddigitalmethods 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 64 Electrical measurements: Introduction and principles of measurement Direct measurement method Gx Gn Ux Un N In equilibrium: Gx=Gn The nullindicator show zero: Ux=Un Weighing Voltmeter 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 65 Electrical measurements: Introduction and principles of measurement Indirect measurement method (cont’) Notes: • Rx=f(Ix) is known! • Automaticalweighing‹ Feedback! • Transient state! 2011.10.24.. TÁMOP –4.1.2-08/2/A/KMR-2009-0006 66 Electrical measurements: Introduction and principles of measurement Differential measurement method Ux Un V Um Ux=Un+Um Um<