Extech Instruments LT40 User manual

Category
Measuring, testing & control
Type
User manual
USERMANUAL
WhiteLEDLightMeter
ModelLT40
AdditionalUserManualTranslationsavailableatwww.extech.com
LT40-en-GB_V3.0 10/17
2
Introduction
CongratulationsonyourpurchaseoftheExtechLT40LEDLightMeterthatmeasureslightintensity
fromwhiteLEDlightsources.TheLT40canalsomeasurelightfromfluorescent,metalhalide,high
pressure sodium, and incandescent sources, for reference only (unspecified accuracy). The LT40
can measure light up to 40,000 Fc (400,000
Lux). This instrument is shipped fully tested and
calibrated and, with proper use, will provide years of reliable service. Please visit our website
(www.extech.com) to check for the latest version of this User Guide, Product Updates, and
CustomerSupport.
Features
OverloadIndication:TheLCDwillshowOL.
LowbatteryIndication.
DisplayUpdateRate:2.5timespersecond.
CosineAnglecorrected.
MeasureswhiteLEDlight.
MeasurestheintensityofilluminationinLuxorfootcandles.
Dataholdfreezesdisplayedreading.
Maximum/Average/MinimumreadingHold.
ZeroCalibrationadjustment.
Autopoweroffwithdisablefunction.
Autorange.
Safety
Donotoperatethemeterinenvironmentswherethefollowingarepresent:explosivegases
(ormaterials),combustiblegases(ormaterials),steam,ordust.
PleasereplacethebatteryimmediatelywhenthelowbatterysymbolappearsontheLCD.
Donottouchthemeter’scircuitboardforanyreason;static
electricityorcontamination
coulddamagethesensitivecomponents.
ForIndooruseonly.Thisinstrumentwasdesignedforpollutiondegree2.
OperationAltitude:Upto2000m(7000’).
LT40-en-GB_V3.0 10/17
3
MeterDescription
1. Photodetector(removeprotectivecovertoexposesensor)
2. Display(LCD)
3. Controlpushbuttons
4. PowerButton:ON/OFF

Batterycompartmentandtripodmountarelocatedon
rearofinstrument
PushButtonDescription
1. Lux/Fcunitsselector
2. ZeroCalibrationbutton
3. Maximum/Average/Minimummemorybutton
4. Dataholdbutton
Operation
PowerON/OFF
LongpressthePowerbuttontopowerthemeter.TopowerthemeterOFF,shortpressthe
Powerbutton.
TakingMeasurements
1. SwitchthemeterONandremovethesensor’sprotectivecovertoexposethelightsensor
dome.ThedisplayshouldswitchON;ifnot,checkthatbatteriesareinstalledandfresh.
2. Themetermeasurestheintensityofthelight(illuminance)thatstrikesthesensordomein
footcandlesandLuxunits(1fc=10.76lux),displayingthismeasuredvalueonitsLCD.
3. Positionthemeterandlightsourcesothatthelightstrikesthesensordomestraighton
(perpendicular)withaslittleanangleaspossible.
4. Themeter’sdisplaycanshowavalueupto9999.However,
forreadingsthatrepresent
measurementshigherthanthis,themeterusesx10orx100feature.Forexample,to
representameasurementof11,000fcthemeterwilldisplay1100withthex10indicator.
LT40-en-GB_V3.0 10/17
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AutoPowerOFF
Tosavebatterylife,themeterpowersdownautomaticallyafterapproximately12minutesof
inactivity.
Enable/DisableAutoPowerOff
WhilethemeterisON,longpressthePowerbuttontodisabletheAutoPowerOFFutility(the
Clocksymbol
willswitchOFF).ToenabletheAutoPowerOFFutility,repeatthisprocess.
LUX/FCButton
PresstheLUX/FCbuttontotogglebetweenLuxandFC(footcandles)measurementunits.
MAX/MINButton
Themetercanrecordthemaximum,minimum,andaveragereadingsasdescribedbelow:
1. Shortpressthe“MAX/MIN”buttonandthemeterwillbegintotrackthe
maximum/average/minimummeasurements;the“MAX”iconwilldisplayatthetopofthe
LCDwindowindicatingthatthemeterisnowshowingthemaximumreading.Thereading
willnotchangeuntilahigherreadingisregistered.
2. Pressthe“MAX/MIN”buttonagaintoswitchfrom“MAX”to“AVG”,wherethemeterwill
showtheaveragemeasurementvalue.The“AVGiconwillbedisplayedabovethedisplayed
value.
3. Pressthe“MAX/MIN”buttonagaintochange
themodefrom“AVG”to“MIN”,wherethe
meterwillshowtheminimumvaluemeasured.The“MIN”iconwillbedisplayed.
4. Pressthe“MAX/MIN”buttonagaintoswitchfrom“MIN”backto“MAX”.
5. Toexitthismode,holdthe“MAX/MIN”buttonforatleast2seconds.TheMAX/AVG/MIN
icons
shouldallbeswitchedOFFwhentheunitreturnstothenormaloperatingmode.
HOLDButton
PresstheHOLDbuttontofreezethecurrentreadingontheLCD.PresstheHOLDbuttonagainto
releasethereading.IntheDataHoldmode,HOLDisdisplayedontheLCD.
ZeroCalibrationProcedure
1. Ensurethattheprotectivecapisattachedtothelightsensor.
2. PowerthemeterandtheLCDshoulddisplay‘0’.
3. Shortpressthe“CALZERO”buttontoperformthezeroadjustment(CALwillappearonthe
display).
4. TheCALdisplaywillswitchoffwhenthecalibration
hasbeencompleted.
5. IftheprotectivecapisnotcoveringthesensorwhentheZerocalibrationisstartedtheLCD
displaywillreadCAP.Inthiscase,pleasecoverthesensorwiththecapandrestartthis
procedure.
LT40-en-GB_V3.0 10/17
5
MeasurementConsiderationsandUserTips
For maximum accuracy allow the light being measured to fall directly on the sensor as
perpendicularaspossiblewithaminimalangleofincidence.
Whenthemeterisnotinuse,pleasekeeptheprotectivecapinplaceoverthelightsensor.This
willprolongthelifeofthesensor.
Whenthemeteristobestored for long periods,pleaseremovethebatteriesandstorethem
separately.Batteriescanleakand
causedamagetothemeter’scomponents.
Avoidareasofhightemperatureandhumiditywhenusingthisinstrument.
BatteryReplacementandMaintenance
Cleaningandstorage
1. Thewhiteplasticsensordomeshouldbecleanedwithadampclothwhennecessary.Use
onlyamildsoapifneeded.Donotusesolvents,abrasives,orharshdetergentstocleanthe
dome.
2. Storethemeterinanareawithmoderatetemperatureandrelativehumidity.
BatteryReplacement
Whenthebatterypowerdecreasestoacriticallevel,thelowbattery
symbol
”willappearontheLCD.Replacethe2x1.5VAAA
batterieslocatedintherearbatterycompartment.
1. Pressandholdthebatterycompartmentlockbutton(seediagram).
2. Slidethebatterycompartmentcoveroffinthedirectionofthe
arrow.
Installtwo(2)1.5V‘AAA’batteriesobservingcorrectpolarity
andclose
thebatterycompartment.Ensurethatthecompartmentcoverissecurely
fastenedbeforeusingthemeter.
Neverdisposeofusedbatteriesorrechargeablebatteriesin
householdwaste.
Asconsumers,usersarelegallyrequiredtotakeusedbatteriestoappropriate
collectionsites,theretailstorewhere thebatterieswerepurchased,
orwherever
batteriesaresold.
Disposal:Donotdisposeofthisinstrumentinhouseholdwaste.Theuserisobligatedtotake
endoflifedevicestoadesignatedcollectionpointforthedisposalofelectricalandelectronic
equipment.
1
2
LT40-en-GB_V3.0 10/17
6
Specifications
Units Range Resolution Accuracy
Lux
999.9 0.1
WhiteLED:
±(3%reading+3Lux)upto500Lux
±(3%reading)>500Lux
Otherlightsources:Unspecified
9,999 1
99,990* 10
400,000* 100
Foot
candles
99.99 0.01
WhiteLED:
±(3%reading+0.3Fc)upto46Fc
±(3%reading)>46Fc
Otherlightsources:Unspecified
999.9 0.1
9,999 1
40,000* 10
*Readingsabove9999useax10orx100multiplier(1Fc=10.76Lux)
Angledeviationfromcosine
characteristics
30° ±2%
60° ±6%
80° ±25%
GeneralSpecifications
Samplingrate 2.5timespersecond(digitaldisplay)
Photodetector Siliconphotodiodewithcosinecorrection
Display4digitLCD(maximumdisplay:9999)withlowbatteryicon,
measurementoverload,andotherfunctionindicators
AutoRangeMeterautomaticallyrangesthedisplay
Operatingconditions Temperature:5to40
o
C(41to104
o
F);Humidity:<80%RH
Storageconditions Temperature:‐10to60
o
C(14to140
o
F);Humidity:<70%RH
Lowbatteryindication
appearsontheLCDwhenbatteryvoltagefallscriticallylow
LEDType WhiteLEDlight
Powersupply 2x1.5V‘AAA’batteries
Batterylife Approximately200hours
AutoPowerOFF MeterswitchesOFFafter12minutesofinactivity
Dimensions 133x48x23mm(5.2x1.9x0.9”)
Weight 250g.(8.8oz.)includingbatteries
LT40-en-GB_V3.0 10/17
7
Appendices
TypicalLightLevels(1Fc=10.76Lux)
Lux Foot
Candles
Lux Foot
Candles
 Factories  Home
2075 27 EmergencyStairs,Warehouse 100150 1015 Washing
75150 715 Exit/EntrancePassages 150200 1520 Recreational
Activities
150300 1530 PackingWork 200300 2030 DrawingRoom,
Table
300750 3075 VisualWork:ProductionLine 300500 3050 Makeup
7501,500 75150 Typesetting:InspectionWork 5001,500 50150 Reading,Study
1,5003,000 150300ElectronicAssembly,Drafting 1,0002,000 100200Sewing
 Office Restaurant
75100 710 IndoorEmergencyStairs 75150 715 CorridorStairs
100200 1020 CorridorStairs 150300 1530 Entrance,
WashRoom
200750 2075 Conference,
ReceptionRoom
300750 3075 CookingRoom,
DiningTable
7501,500 75150 ClericalWork 7501,500 75150 ShowWindow
1,5002,000 1502000 Typing,Drafting 
 Store Hospital
75150 715 Indoors 3075 37 EmergencyStairs
150200 1520 Corridor/Stairs 75100 710 Stairs
200300 2030 Reception 100150 1015 SickRoom,
Warehouse
300500 3050 DisplayStand 150200 1520 WaitingRoom
500750 5075 Elevator 200750 2075 MedicalExamRoom
7501,500 75150 ShowWindow,
PackingTable
7501,500 75150 OperatingRoom
1,5003,000 150300Storefront,ShowWindow 5,00010,000 5001000 EyeInspection
Copyright©20132017FLIRSystems,Inc.
Allrightsreservedincludingtherightofreproductioninwholeorinpartinanyform
ISO9001Certified
www.extech.com
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Extech Instruments LT40 User manual

Category
Measuring, testing & control
Type
User manual

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