>> P.351
Detectionprincipleofelectromagneticinductionscale(ABSST700,ABSAT1100)BasicoperationprincipleofelectromagneticinductionsystemL1CoilA〜V2VI1I2L2CoilB[Figure1]ElectromagneticinductionsystemencoderprincipleWhenacurrent(I1)thatchangesovertimeispassedthroughcoilA,amagneticfluxiscreatedinthevicinityofcoilA.Thiscausesaninductivecurrent(I2)toflowincoilB,inadirectionthatcancelsoutthemagneticfield.Magneticpermeabilitybetweencoilsislargelyidenticalinair,water,oroil.Electromagneticinductiontypesensorhasexcellentwaterresistanceandoilresistance.PVoltage(V)DetectingcoilDisplce-mentExcitercoiPSensorsectionScalcoilDisplcementmagnitudeMulti-trackdesignallowsconfigurationofabsoluteencoderCoilsarrangedatconstantpitchonscale[Figure2]DetectionprincipleofelectromagneticinductionscaleElectromagneticinductionisaphenomenonthatoccurs,forexample,whentwocoilsarearrangedfacingeachother,asshowninFigure1,andatime-varyingcurrent(I1)ispassedthroughcoilA.Thiswillcauseaninducedcurrent(I2)toflowincoilB,inadirectionthatcancelsoutthemagneticfield.Theelectromagneticinductiontypelinearscaleusesthisphenomenontoconvertadisplacementmagnitudeintoanelectricalsignal.TheoperationalprincipleofthesensorsectionisshowninFigure2.Anumberofscalecoilsarearrangedwithprecisespacingonthemainscale.Themoveablesensorsectionthatdetectsdisplacementcarriesanexcitercoilandacorrespondingdetectorcoil.Acurrentissentthroughtheexcitercoil,therebycreatingamagneticfluxthatinducesacurrentinthefacingscalecoil.Themagneticfluxcreatedinturnbythatcurrentinducesacurrentinthefacingdetectorcoil.Thedegreeofinductivecouplingbetweenthecoilschangesaccordingtothedisplacementmagnitudeofthesensorsection,allowingasinusoidalsignalwithacyclethatcorrespondstothepitchofthescalecoilstobeobtained.Byusinganelectricalcircuitthatperformsinterpolation(division)ofthissinusoidalsignal,displacementcanbemeasuredwithfineresolution.Two-sidedTelecentricOpticalSystemPrinciple(ABSST1300,ABSAT1300)Linearencoderequippedwithtwo-sidedtelecentricopticalsystemimagingLight-receivingdeviceZXYLight-receivingdeviceLightsource+Two-sidedtelecentricopticalsystemScaleDeepfocaldepthTwo-sidedtelecentricopticalsystemZXScaleDetectionPrinciple•Thescalegratingiscapturedasanimagewiththetwo-sidedtelecentricopticalsystemanditsdisplacementisdetectedwithalight-receivingdevice.WideimagingrangeFeatures•Adoptionofatwo-sidedtelecentricimagingopticalsystem⇒Improvestherobustnessoftheencoder.•Thedeepfocaldepth⇒ExtendsallowanceforGAPvariation(scalewavinessandstageorientationvariation,detectormountingvariation,etc.).•Thewideimagingrange⇒Extendsallowanceforcontamination,slightdamage,etc.onthescale.8-64
| < 
| 
> | 
>>
