XITRON XT2640 - Page 43

XT2640OperatingManual 13July2016 Page43of187

Recommendations:
TheAUTO‐TRACKselectionisrecommendedformostapplicationsunlessasetbandwidthornolimitatallisspecifically
requiredbytheapplicationorifmeasuringfrequenciesclosetoorabovethemaximummeasurablefrequencyofthe
channels.
Note:
Ifthebandwidthrestrictionisbeyondthecapabilitiesofachannelthennobandwidthlimitationisapplied.
IfyouselectAUTO‐TRACKthenyoucanreturntothisscreenandseetheactuallyappliedlimit,whichisdisplayedinthe
lowerhalfofthisbutton,e.g.AUTO(6k).
IfyoualsoselectNONEastheFUNDsetting,thenafixed500Hzbandwidthlimitationisused.
Seesection16forfulldetailsregardingconfiguringthisformeasurementsonPWMgeneratedsignals.
12.4.2.2.4 ConfiguringHar monicAnal ysis
TheHARMONICSbuttonallowsyoutoselectthemaximumnumberofharmonicstoanalyzewithintheVPAbeingconfiguredifMEAS
MODEisnotEN61000‐3‐2orEN61000‐3‐12.ThisisnotavailablewhenMEASMODEissettoSPECTRUMorifFUNDissettoNONE.
Recommendations:
Formostapplicationsthisshouldbesetto50unlessharmonicanalysisisnotrequiredinwhichcaseitshouldbesetto0.
Onlyifthespecificapplicationrequiresmoreharmonicsisitrecommendedtosetthishigher.
Inmodulatedsignalapplications(suchasmotordrives)thisshouldbealowvalueandoftenafigureof5orlessisused.
Notes:
Ifthisissetto0thennoharmonicswillbeanalyzedintheVPAbeingconfigured.
Lead/lagandallnon‐harmonicmeasurementsarestillavailablewhennotperformingharmonicanalysis.
Inordertoaccuratelymeasureveryhigh‐orderharmonicsthecycle‐to‐cyclejitterofthesignalfrequencyisofimportance.
Toaccuratelymeasure500harmonicsthisrequiresthatthesourcehave<0.025%frequencyjitter.Mainssuppliesrarely
achievethis.Ifitisdesiredtomeasurehigh‐orderharmonicsofanunstablefrequencysourcethenitisrecommendedthat
youconsiderusingspectrumanalysisinstead.
Theactualnumberofavailableharmonicsislimitedtohalfthebandwidthlimitation,andmaybefurtherlimitedbyother
settingsand/orbythemeasuredfundamentalfrequency.
Seesection16forfulldetailsregardingconfiguringthisformeasurementsonPWMgeneratedsignals.
12.4.2.2.5 ConfiguringSp ectrumAnal ysis
TheSPECTRUMbutton(notshownintheexamplescreenabove)allowsyoutoenterthedesiredfrequencyresolution(inHz)and
maximumdesiredfrequency(inHz)forthespectrumanalysis.ThisisonlyavailablewhenMEASMODEissettoSPECTRUM.
Note:
Thesesettingshaveamajoreffectonthespeedatwhichspectrummeasurementscanbemade,forbestspeedusethe
largestpossiblefrequencyresolutionandthesmallestpossibleratiobetweentheresolutionandmaximumfrequencies.
Thefrequencyresolutionentryislimitedtobewithin0.01Hzto1kHz
Themaximumfrequencyentryislimitedtobetween100and16384timesthefrequencyresolution.
12.4.2.3 CONFIGURINGHO WMEASUREMENTRESULTSAR EDISPLAYED
ThisisperformedbyusingthebuttonsintheDATAarea.Dependingonconfigurationandtheinstalledchannelssomebuttonsmay
notbepresentormaynotallowmodificationofthesetting.
12.4.2.3.1 Settingth eDefaultCouplingforDa ta
TheCOUPLINGbuttonallowsyoutoselectwhetherDCONLY,ACONLYorAC+DCresultswillbeshownastheprimarydataonthe
POWERDATAscreens,andusedforthecalculationofintegrateddata,andusedforobtainingtotalvaluesfortheselectedVPA.
Recommendation:
UnlessitisknownthatonlytheDCresultsarerequiredthentheAC+DCsettingisrecommended.
Note:
DCONLYisnotavailableifMEASMODEisEN61000‐3‐2orEN61000‐3‐12.
Thisdoesnotrestrictchannelmeasurementdatatotheselectedcoupling;themeasurementresultswithinachannelare
alwaysavailableforallcouplings.
12.4.2.3.2 SettingforResultAveraging
TheRESPONSEbuttonallowsyoutoselectthatmeasurementresultswillbeaveragedovertimeifMEASMODEisnotEN61000‐3‐2
orEN61000‐3‐12.
SettingsofFASTEST,MEDIUM,SLOWandSLOWESTareavailable.
Recommendation:
TheperformanceandspecificationsoftheXT2640arenotreliantontheuseofthiscapability;itshouldbeusedwhen
neededandotherwisesettoFASTEST.
WhenusingresultswhicharedependentonresultsfrommultipleVPAsorfrommotorresultsthentheseresultsmaynot
allbeusingthesameresponseaveraging,whichmayresultininappropriateresultswhilethesignalsarechanging.In
thesecasesitisrecommendedtouseFASTESTforallresponseaveragingsettings.
Note: