5.3.2Time
Tosettheflashduraoninmeinsteadofdegrees,pressthe
MENUbuonagain(skiptheDEGmenu).
Usethearrowsonthejoyscktoadjusttothemevalue.
Timecanbesetfrom0.001mSecto2.000mSec.
PresstheMENUbuonfollowedbythePowerbuon
tosavethemeseng.
Toexitwithoutsengtheflashduraoninmepressthe
Power.
5.4DECPT(DecimalPoint)Menu
TheDecimalPointmenuadjuststheresolutionoftheFlash/Tachrate
displayed.Uptothreeplacesafterthedecimalpointcanbeshown.
Thenumberofdecimalplacesislimitedbythe6‐digitsavailableand
theunitwillautorangetoshowthemaximumnumberofdigitsafter
thedecimalpointselectedbytheuser.ThechoicesareNONE,1,2,
3.Avalueof600willbedisplayedas600,600.0,600.00,600.000
dependingonthesetting.
PresstheMENUbuttontoentertheDECPTmenu.Thecurrent
valueisshownonthetoplinewithDECPTonthelowerline.The
On‐Targetindicatorwillbeonforthecurrentlyselectedvalue.
Usethearrowsonthejoyscktoselectthedesiredvalue.
PresstheMENUbuonfollowedbythePowerbuon to
savethedecimalpointseng.
ToexitwithoutsengthedecimalpointpressthePower
buon.
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5.4UNITSMenu
ThismenuoponselectstheEngineeringUnitsusedtodisplaythe
flashrateorspeed.Thechoicesare:
FPM‐FlashesperMinute(NotavailableinTACHMode)
FPS‐FlashesperSecond(sameasHz,notavailableinTACHMode)
RPM‐RevoluonsperMinute
RPS‐RevoluonsperSecond(sameasHz)
PresstheMENUbuontoentertheUNITSmenu.Unitis
shownonthetoplinewiththecurrentengineeringunitonthe
lowerline.TheOn‐Targetindicatorwillbeonforthecurrently
selectedvalue.
Usethearrowsonthejoyscktoselectthedesiredvalue.
PresstheMENUbuonfollowedbythePowerbuon
tosavethevalue.
ToexitwithoutsengtheunitspressthePowerbuon.
6.STROBEBRIGHTNESS
Thestrobe’sbrightnessdependsonhowwidethestrobe’sflashpulseis;the
widerthepulse,thebrightertheflashfromtheLEDsappearstobe.Thereis
however,adownsidetothewiderpulses.Allstrobesworkbygivingshort
burstsoflight(thepulsewidth)atarapidrepetitionrate(theflashrate).
Strobesrelyonthepersistenceofthehumaneye(theabilitytoremember
andimage)anditsresponsetobrightlighttogiveanapparentstopmotion
image.Imagineashaftrotatingat6000RPMoronerotationevery1/100of
asecond(10msec).Ifthestrobeflashesonceevery10msecforabrief
moment,theuserseestheflashatthesamespotintherotationoftheshaft
andthepersistenceoftheeyeremembersthisuntilthenextflashmaking
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theshaftappearedtobestopped.Asthetargetisrotatingthereissome
movementevidentduringthestrobeflash.Thelongertheflashduration,
themoreobvioustherotationisandthisincreasestheblur.
6.1CalculangBlur
Blurcanbecalculated–iftheshaisturning
at6000RPM,ittakes10msectocomplete
onerevoluon.Ifthestrobeflashduraonis
100µsec(1/100ofamillisecond),thesha
willturn:
(flashduraon/meperrotaon)x360°,
whichis(.0001/.01)x360=3.6°.Soyouwill
seetheshaappeartomove3.6°.
Astheflashpulsewidensyouwillseegreater
degreesofrotaonwhichresultsinmoreblur
andabrighterperceivedilluminaon(the
LEDsareonlongersotheaveragelightthe
eyesseeisgreater).Thetradeoff isblur
versusbrightness.Thefurtherawaythe
rotangpointisfromthecenteraxisthe
fasterthetangenalvelocityandtheworsetheblurappearstobe.
Whensengthepulseduraonindegrees,whatyousetiswhat
youget.Refertotheimageontherightforthedifferencebetween
a1°and5°(ofrotaon)flashduraon.
Therearetwomethodsofadjusngtheflashpulsewidthandhence
thebrightnessandconsequentlytheblur.ForsengBrightnesssee
secon5.3.
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6.2BrightnessinDegreesofRotaon
Brightnesscanbesetfrom0.2to14degreesoutof360.Thehigher
thesengthebrighterthestrobeappearstobebutthemore
blurredthetargetis.Opmalsengtostopmoonis1.8to3.6°.
Thenumberofdegreesisaproporonalamountandremains
constantastheflashrateincreasesordecreases.Thestrobe
automacallycalculateshowwidethepulsewidthshouldbeat
differentflashratestokeeptheblurconstant—thefastertheflash
ratethenarrowerthepulsewidth.Thepulsewidthequals:(seng
indegrees/360)x(1/flashrateinHz).
6.3BrightnessinPulseDuraon
Brightnesscanalsobesettoafixedduraonpulseinmilliseconds.
Theflashrateremainsconstantirrespecveoftheflashrate,thusas
theflashrateincreases,theimagewillgetbrighterandmore
blurred.
Note:Therearetwolimitsmaintainedbythestrobe–theflash
pulsewidthcanneverbegreaterthan2.0msec(milliseconds)nor
canitexceed14°ofrotaon.
Thestrobeautomacallyadjuststhepulsewidthandrotaonvaluesas
theflashrateisincreasedordecreasedtomaintainthelimitsatall
mes.Forexample—aflashrateof600flashesperminute(10Hz),14°
ofrotaonrepresentsaflashpulsewidthof3.8msec.Thestrobewill
limitthisvalueto2.0msecor7.3°ofrotaon(blur).
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