XITRON XT2640 - Page 65

XT2640OperatingManual 13July2016 Page65of187
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12.10 .2.3 RUNNINGASCOPECAPTURE
TheoscilloscopemayberunineitherSINGLEorCONTmodessimilarlytoanormaloscilloscope.
PressingtheCONTbuttonstartscontinuousoscilloscopecaptures.
WhilecapturinginCONTmodethebuttoniscoloredgreenandislabelledRUNNING.Shortlyaftertriggeringandcapturing
allsignals,thescopewillwaitforanothertriggerevent.WhilecapturinginCONTmodeyoumaypresstheCONTbuttonto
stopcapturingsignals,ormaypressthebuttontoitsrighttomakeaSINGLEmodecaptureinstead.
PressingtheSINGLEbuttonstartsasingleoscilloscopecapture.
WhilecapturinginSINGLEmodethebuttoniscoloredgreen.Aftertriggeringandcapturingallsignals,thescopewillstop.
WhilecapturinginSINGLEmodeyoumaypresstheSINGLEbuttontoabortthecapture,ormaypresstheCONTbuttonto
initiateCONTmodeinstead.
Whilecapturing,theSINGLEbuttonislabelledwiththestatusofthescopesignalcapture‐
PRETRIG.Indicatesthatthescopeiscollectingsufficientsignaltoaccommodatetheconfiguredtriggerposition.
WAITING.Indicatesthatthescopeiswaitingforatriggerevent.
TRIG’D.Indicatesthatthescopeiscollectingthesignalsafteratriggereventhasbeendetectedbutthereisnotenough
signalcapturedtofillthescreenyet.
Recommendations:
TheBANDWIDTHsettingfortheVPAalsobandwidthlimitsallsignalsforthescope.Thiscanlimityourabilitytousethe
HFtriggertypeifsetforafasttimebase.IfyouintendtousetheHFtriggertypetodetectveryfastglitchesonamuch
lowerfrequencysignalthenitisrecommendedtoconfiguretheVPAmeasurementsforanBANDWIDTHsettingof
UNFILTERED.IfusingtheINRUSHcapturemodethentheBANDWIDTHisignoredduringthescopecapture.Theactual‐
3dBbandwidthofthecapturedsignalsisdisplayedbelowthechart.
Iftheintentionistotriggeronaninrushevent,thentheuseoftheABS(DC)triggertypeisrecommended,usingthecurrent
signalasthetriggersourceandsettingthetriggerleveltoasuitablecurrentlevelwhichyouexpecttheinrushcurrentto
exceed.TypicallySINGLEcapturesareusedforinrushcapture.
IftheintentionistotriggeronamainssupplysurgethentheABS(DC)triggertypeisrecommended,usingthevoltage
signalasthetriggersourceandsettingthetriggerleveltoasuitablevoltageleveljustabovethepeaklevelofthehighest
expectednormalmainsvoltage.TypicallyCONTmodeisusedformainssupplysurgecaptureasthisenablestheXT2640to
detectanothersurgewithoutuserintervention.
Iftheintentionistotriggeronmainssupply‘glitches’thentheHFtriggertypeisrecommended,usingthevoltagesignalas
thetriggersourceandsettingthetriggerleveltoavoltageleveljusthighenoughtonottriggeronwhateverglitchesare
normallypresent.TypicallyCONTmodeisusedformainssupplyglitchcaptureasthisenablestheXT2640todetect
anotherglitchwithoutuserintervention.
ForcapturingrepetitivesignalsthentheuseoftheDC(rising)orDC(falling)triggertypesisrecommended,howeveryou
shouldalsoconsiderusingCYCLEVIEWasthisprovidesbettertraceresolutionintimeandrequiresnoconfiguration.
Justasforalldigitalsamplingoscilloscopes,settingthetimebasetoaverylongvalueandattemptingtocaptureahigher
frequencysignalwillcausealiasinginthecaptureddatamakingthecapturedsignallooklikeithasamuchlowerfrequency
thanitactuallyhas.TheXT2640hasaninternalscopecapturedepthof32768samples.Youshouldalwayssetan
appropriatetimebaseconsideringthefrequencyofthesignalexpected.
Note:
Sincethescopeviewcaptureisintendedforthecaptureofnon‐repetitivesignalsitgainsnoadvantagefromtheadvanced
samplingsystemintheXT2640andscopeviewdatahasthetimeresolutionofindividualsamplesofthesignals.ForW
channeltypesthisisjustover1µs,otherwiseitisjustover4µs.
12.10 .2.4 VIEWINGA SCOPECAPTURE
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Thelasttakenscopecaptureisshownwiththetracesselectedandconfiguredasdescribedabove.Totheleftofthechartisalisting
oftheconfiguredtraces.Belowthechartisatextualdescriptionofthetriggerconfiguration.
Note:
IfnosignalshavebeencapturedthenNODATACAPTUREDisdisplayedonthechartandthechartisblank.