光电编码器的特性及应用.docx

光电编码器的特性及应用.docx

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光电编码器的特性及应用

Thepropertiesandapplicationofphotoelectricencoder

Theworkingprinciple,photoelectricencoder

Photoelectricencoder,isakindofphotoelectrictransformationthroughthemachinewilloutputshaftgeometricdisplacementconvertpulseordigitalsensors.Thisisthemostsensor,photoelectricencoderandgratingisbyphotoelectricdetectiondevice.Gratingisincertainpartsofthediameterofthecircularplatetoopenseveralrectanglehole.Causedbythecode,motorandmotorcoaxialrotatesgratingandmotorrotatespeed,withthelightemittingdiodeandotherelectroniccomponentstestingunitoutputpulsesignalwithseveral,itsprinciplediagramisshowninfigure1,Throughthecalculationoftheoutputpulseofphotoelectricencoderpernumbercanreflectthecurrentmotorspeed.Inaddition,thedirectionofrotation,thecodeforthejudgemayalsoprovidephasedifferencedishof90ºtwopulses.

Accordingtothemeasuringprinciple,encodercanbedividedintoopticalandmagnetictype,inductiveandcapacitor.Accordingtothecalibrationmethodandthesignaloutputform,canbedividedintoincremental,absolutelyandhybridthree.

Incrementalencoder

IncrementalencoderisdirectlyfortheuseofphotoelectricpulseoutputthreesquareprincipleofAandBandZ,AandBgroupphase,pulse90ºcaneasilyidentifyrotationdirection,andforeveryturnAphaseZbenchmarkforpositioning.Pulse,Itsadvantagesaresimplestructure,mechanicalprinciple,averagelifeexpectancyintensofthousandsofhours,stronganti-jammingcapability,highreliability,suitableforlongdistancetransmission.Itsdefectisnottheabsoluteoutputshaftrotationlocationinformation.

图1光电编码器的远离示意图

Absolutephotoelectricencoder

Absoluteencoderisdirectdigitaloutputsensor,initscircularyardsonseveralconcentricyardsalongtheradialdirectionofeveryfaith,bypervioustolightandnotpervioustolight,thesectorandtheadjacentcodenumberofsectors,encoderisdoublethecodenumberofbitsofitinthecodeofdigits,lightsource,theothersideisonewordhasacorrespondingyardphotosensitivecomponents,Whenthecodeindifferentposition,thedishbyvariousphotosensitivecomponentsaccordingtothecorrespondingconversionorlightsignals,binarynumberlevel.Thisisnottheencodercounterintheshaftcanbereadatanypositionofafixedpositioncorrespondswiththedigitalcode.Obviously,theword,themorethehighresolution,foraNbinaryresolutioncodercodesalvermusthaveNbarcode.Currentlythereare16bitsofabsoluteencoderproducts.

Singlechannelabsolutephotoelectricshaftencoderisusingthenaturalbinaryorcircularbinary（Gregoryyards）mannerphotoelectricconversion.Absolutephotoelectricencoderandincrementalencoderdiffersnotpervioustolightonthedisk,theline,absoluteencodersmayhavegraphics,accordingtothenumberofcodereadcodeoncoding,detectionabsoluteposition.Codedesigncanusebinarycode,circulation,binarycomplement,etc.Itsfeaturesare:

CanreadAngleofabsolutecoordinatesdirectly.

Noaccumulativeerror.

Powerexcisionlocationinformationwouldbelost.Buttheresolutionisdeterminedbythebinarydigits,i.e.,precisiondependsonthemedian10,14etc.

Hybridabsoluteencoder.

Hybridabsoluteencoders,itsoutputoftwogroups:

agroupofinformation,informationfortestingpoleswithabsoluteinformationfunction,Anothergroupofincrementalencoderiscompletelywiththeoutputinformation.

PhotoelectricencoderisanAngle（angularvelocity）detectiondevice,itwillinputshaftAnglefor,usingtheprincipleofphotoelectricconvertelectricalordigitalaccordingly,smallsize,highaccuracy,highreliability,digitalinterface,etc.Itiswidelyappliedinncmachinetools,turningmachine,servodrive,robots,radarandmilitarytargetswereneededintheAngleofdeviceandequipment.

Appliedcircuitofphotoelectricencoder

EPC-755Aapplicationofphotoelectricencoder

EPC-755AphotoelectricencoderandtheuseofgoodperformanceinAnglemeasurement,displacementmeasurement,andhasstronganti-jammingcapabilityoftheoutputpulsesignalisstableandreliable,andthepulsesignalcanbeobtainedbycountingweremeasuredafterthedigitalsignal.Therefore,weinthecardrivingsimulators,steeringwheelrotationAnglemeasurementchoosesEPC-755Aphotoelectricencoder,theoutputcircuitassensors,chooseopencollectoroutputresolutionselection360pulse/circle,consideringthesteeringwheelrotationisatwo-waystreet,clockwiseandcounterclockwise,canalsoneedstotheoutputsignalphasecodertocount.Figure2showstheactualuseofphotoelectricencoderanddiscrimination,phasetwo-waycountscircuitwithaDflip-flopcircuitandtwocross-couplednandgates,with74LS1933countscircuit.

图2光电编码器鉴相计数电路

Whenthephotoelectricencoderclockwise,channel,AleadingchanneloutputwaveformofoutputwaveformB90°,Dflip-flopoutputwaveformW1）forQ（highlevel,Q（W2）forlow-levelwaveformcross-couplednandgates,open,countingpulsewaveformW3）by（bidirectional,sendtothe74LS193counterCUinputpulses,addcount,Atthistime,below,itsoutputcross-couplednandgatescloseforhighlevel（waveformW4）.Whenthephotoelectricencodercounter-clockwise,channelAoutputwaveformofoutputwaveformdelaythanchannelB90°,Dflip-flopoutputwaveformW1）forQ（lowlevel,Q（W2）forhighlevelwaveform,theoutputcross-couplednandgatesclose,highlevel（waveformW3）,Now,twocross-couplednandgatesopen,countingunderimpulsivethrough（waveformW4）,sendtotwo-way74LS193counterreducedinputpulses,CD.Subtraction.

Steeringwheelclockwiseandcounter-clockwise,themaximumrotationAnglefortwolaps,chooseresolutionfor360pulse/circleoftheoutputpulsecoder,itsbiggestfor900,Actualusethreeslicesofcountscircuit74LS193componentinthesystemofinitialization,thesignalreset（CLR）,theinitialsetfor800H,namely2048（LD）;thesignal,So,whenthesteeringwheelclockwise,counttheoutputcircuitfor2048~2948,whensteeringcounter-clockwise,counttheoutputcircuitfor2048-804,D0outputdatacountscircuitD11~todataprocessingcircuit.

Inpractice,thesteeringwheelfrequentlymadeclockwiseandcounterclockwiserotation,becauseexistence,worklongerquantizationerrorafteraperiodoftime,thesteeringwheelwhentheoutputofacircuittocount,butmaynot2048severalwordsdeviation,Tosolvethisproblem,weaddedasteeringwheeltodetectcircuits,systems,dataprocessingcircuitafterworkontheoperationstateinthesimulator,systemtestintheback,ifdetectioncircuitinthebackwheel,andcountscircuitinthedataoutput,butnottocount2048resetcircuit,andtheinitialreset.

Photoelectricencodergravitymeasurementinstrumentintheapplication

Therotaryphotoelectricencoder,theshaftandgravitymeasuringinstrumentforknobshaft.Gravitymeasurementoftheangulardisplacementvolumeknobcompensationforasignalistransformed,Rotaryphotoelectricencoderandabsoluteencodertwopointsandincrementalencoder.

Incrementalencoderistheoutputpulseform,itscodeplatesensorthanabsoluteencodercodeeasiertodiskandhigherresolution.Generallyneedonlythreebarcode,here'scodehasnotactuallyhadwordofabsoluteencodercode,butproducecountingpulse.It'scodeofWaiDaoandmiddlewayhasthesamenumberofuniformdistributionofnotpervioustolightandsector（raster）,butistwosectormutualstaggerhalfarea.Whenthecodesalver,turningtheoutputsignalisAdifferencefor90°withBinthepulsesignalandonlyonethirdoftheslitperviouswordcodegeneratedbythepulsesignal（itasthebenchmarkcodesalverposition,toprovideaninitialcountingsystemofzerosignal）.FromA,Btwooutputsignalphaserelationship（aheadorbehind）canjudgethedirectionofrotation.Graph3by（a）,whenthecodedishisaword,pulsethanBgroundPI/2,andreverse,awordthanBlaggingwayspulsesPI/2.Figure3.（b）isApracticalcircuit,useAwordofplasticwavealongthesteady-stateproducessingletriggerwordandbarepulsewavephase'and'plasticdisc,whenthecodeisonlypositivemouthpulseoutput,whereasonlyreversemouthpulseoutput.Therefore,theincrementoftheoutputpulsecoderisaccordingtothesourceandpulsecounttodeterminethedirectionandthecodesalver.RelativeangularUsually,iftheencoderhasN（yards）,itsoutputsignalphasedifferenceofPI/N,maycountforthenumberoftimesthegrating2Npulse,N=2.Figure3circuitfaultsaresometimesmistakepulse,thiserrorinasignalinahigh"or"low",and"levelothersignalisin"high"and"low"andchangeofstate,thoughcodesalver,butwillproduceashiftintheoutputpulse.Forexample,codesalverormanualalignmentoccursjitterposition（belowcansee,inspringgravimetersmeasurementwillhavethiskindofcase）.

图3增量光电编码器基本波形和电路

图4四倍计数方式的波形和电路

Figure4isacanpreventerrorandcanimprovetheresolutionofthepulsefrequencysubdivisioncircuitfourtimes.Here,thefunctionofmemoryisDflip-flopandclockgenerator.Figure4shows,byeverytwoDflip-flop,sotakeintheclockpulse,theintervaloftwoQend（suchasthecorrespondingB74LS1752,7foot）maintaintwoclockperiod,ifbothinputstatus,saidthechangein,Otherwise,canaccordingtotherelationshipbetweenthechangesfromtheparty,whichis"to"or"backward"outputpulse.Whenawordbecauseofhighvibrationinthe'','low",willchangebetweenreciprocatingalternate"positive"and"backward"pulse,thetwocounteronthenumberandreplacethemwhentheycane