Ametek LAND LSP HD Series - 2.6 Installation Precautions; Vibration, Reflections, and Window Compensation

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User Guide LSPHD Linescanner Head
2.6 Installation Precautions
2.6.1 Vibration
ItishighlyrecommendedthattheLSPHD Linescanning Thermometer is positioned in a
locationwherevibrationiskepttoaminimum.
2.6.2 Infrared reections
Allpracticaltargetshavesomereectivitywithintheinfraredwaveband.This
reectivityincreasesasthetargetemissivityreduces(seeSection5.0).Therefore,the
scannerseessomeradiantheatenergyfromreectionsofsurroundingobjects,aswell
asfromthetargetsource.Thisenergyisnotusuallysufcienttohaveaneffectonthe
measurement,buttakecaretoensurethatobjectsofsimilarorhighertemperatureto
thetargetarenotplacedwherereectedenergymayenterthescanner.
2.6.3 Compensating for losses in viewing windows
TheemissivitycontrolontheLSPHDcanbesettocompensatefortargetemissivity
andwindowlosses(suchaswhenusingtheLSPSealedtoProcessFlange).Asimple
calculationprovidesthecorrectsetting,asfollows:
Forexample:ifviewingatargetofemissivity0.8throughasapphirewindowthe
effectiveemissivitysettingshouldbetheproductofthesurfaceemissivityandthe
transmissionofthesapphire.Transmissionis100%minusthereectionlossofeach
surface(7%+7%)=86%.Theequivalentemissivitysettingtoovercomethisloss
maybecalculatedasfollows:1-(losses)/100whichequals0.86.
Thisvalueshouldthenbemultipliedbythevalueoftargetemissivity.Henceemissivity
setting = 0.86 x 0.80 = 0.69
Note
Ensureyouchooseanappropriatewindowmaterialforthespectralresponseof
the LSPHDscanneryouhave.Formoreinformation,contactAMETEKLand.