Extech Instruments CG304 User manual

USERGUIDE
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CoatingThicknessTester
With Bluetooth®
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ModelCG304

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Introduction
CongratulationsonyourpurchaseoftheExtechCG304CoatingThicknessTester.TheCG304isa
portablemeterdesignedfornon‐invasivecoatingthicknessmeasurementswithautomatic
recognitionofthematerialundertest.
Themeterusestwomeasurementmethods:magneticinduction(forferrousmetalsubstrates)
andeddycurrent(fornon‐ferrousmetalsubstrates).
TheBluetooth®featurewirelesslytransmitsmeasurementdatatoaPCforfurtheranalysisand
togeneratereportdocumentation.
Properuseandcareofthismeterwillprovidemanyyearsofreliableservice.
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Description
MeterDescription
1. LCDdisplay
2. Powerkey
3. Probe
4. ARROWbuttons
Note:Batterycompartmentonrearofmeter

DisplayIconDescription
NFeNon‐ferrousmetals
FeFerrousmetals
AUTO Automaticsubstraterecognition
ForN Calibrationicons
DIRDIRECTmode
GRO1…4 GROUPModenumber
µmMicrometersunitofmeasure
milsmils=millimeters*2.54/100
mmMillimetersunitofmeasure
AVGAveragereading
MINMinimumreading
MAXMaximumreading
SDEV StandardDeviationreading
NONumberofdatapoints
Lowbattery

Note:TheunitofmeasureiconflasheswhenintheCONTINUOUSmodeofoperation.The
unitofmeasureiconisstablewhenintheSINGLEmodeofoperation.
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QuickStartInstructions
MeterPower

PressthepowerbuttontoswitchthemeterON.ThedisplaywillswitchON.Ifthedisplaydoes
notswitchON,installorreplacethebatteries.
Measurements

Usethefilmreferencesandzeroreferencemetalsubstratestolearnhowthemeteroperates
beforemovingtoaprofessionalapplication.Theroundmetalsubstrateistheferrous(magnetic)
substrateandtherectangularshapedmetalsubstrateisthenon‐ferrous(non‐magnetic)
substrate.Themeterautomaticallysensesferrousandnon‐ferroussubstrates.
1. Placeareferencefilm(250µm,forexample)ontheround,ferroussubstrate.
2. Placethespring‐loadedmetersensoragainstthereferencefilm.
3. Inthesinglemodethemeterwillemitanaudibletoneindicatingthatthemeasurement
hasbeentaken.
4. Inthecontinuousmodethedisplaywillcontinuallymeasureandupdatethedisplay
5. TheLCDwillshowthereading(250µm)atthecenterofthedisplayarea.
6. Atypicaldisplaywillalsoshowthefollowing:
NO=1(readingnumberone)onthelowerleftoftheLCD
AVG=250µm(runningaverage)onthelowerright
DIR=DIRmodeofoperationontheupperleft
Fe=FerroussubstrateontheupperrightoftheLCD

Experimentwiththeremainingreferencefilmsandthesubstratebeforeusingthemeter
professionally.
AutomaticPowerOFF
Inordertoconservebatterylife,themeterwillautomaticallyturnoffafterapproximately10
minutes.Todefeatthisfeatureusetheprogrammingmenudetailedinthenextsection(menu
parameterAUTOPOWEROFFunderOPTIONS).

DIR
um
AVG=250 NO=1
250
Fe

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ProgrammingMenu

Themetercanbeconfiguredandcalibratedthroughsimplebuttonpressesintheprogramming
menu.PresstheLEFTbuttontoaccessthemenuandrefertothemenu‘tree’below.Themenu
usesUP/DOWN,LEFT/RIGHTpressesfornavigationandselection.Inthetablebelowthefactory
defaultsettingsareinboldwithanasterisk.Eachparameterisexplainedindetailinthe
subsequentsections.
ToplevelSublevel1Sublevel2Notes
STATISTICALVIEW
AVG*Averageofaseriesofreadings
MIN Lowestofaseriesofreadings
MAX Highestofaseriesofreadings
NONumberofsampledreadings
SDEV Standarddeviationofaseries
OPTIONS
MeasuremodeSingle*Onereadingatatime
ContinuousContinuousmeasurements
WorkingmodeDirect*Readingsarenotstoredingroups
Group1…4Storereadingsingroups
Probeused
Auto*Meterautomaticallyselectsmode
FeFerrousmeasurementmode
NoFeNon‐ferrousmeasurementmode
Unitsettings
µm*Micrometers
milsMils=mm*2.54/100
mmMillimeters
BacklightON*Enablesbacklightoperation
OFFDisablesbacklightoperation
LCDStatistics
AVG*Averageofaseriesofreadings
MAXHighestofaseriesofreadings
MINLowestofaseriesofreadings
SDEVStandarddeviationofaseries
AutoPowerOFFEnable*Allowsautopowerofftooperate
DisableDefeatstheautopowerofffeature
LIMITLimitsettingsHighLimitHighAlarmalertsuserwhenreached
LowLimitLowAlarmalertsuserwhenreached
DeleteLimits Clearthealarmlimitvalues
DELETE
CurrentData Deletecurrentdata
AllData Deleteallstoreddata
GroupData Deletedatastoreddataplusalarmand
calibrationdata
MEASUREMENT
VIEWViewstoreddatainallgroups
CALIBRATION
Enable Allowcalibrationaccess
Disable Lockoutthecalibrationmode
DeleteZeroN Clearthezerocal.data(non‐ferrous)
DeleteZeroF Clearthezerocal.data(ferrous)
NOTE:DisabletheAutoPowerOFFfeaturebeforelengthyprogrammingtoavoidinconvenientautomatic
powerdownwhileprogramming.

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STATISTICALVIEWSMenu
1. PresstheLEFTbuttontoaccesstheprogrammingmenu
2. PresstheLEFTbuttontochooseSTATISTCALVIEW
3. UsetheUPandDOWNbuttonstoscrollthroughtheAVERAGE,MINIMUM,MAXIMUM,
NUMBEROFDATA,andSDEV(StandardDeviation)valuesforthestoredreadings.
4. ‘NODATA’willdisplayifnoreadingsareavailableforthemetertoanalyze.Storedreadings
willclearwhenthemeterpowersdownunlesstheGROUPfeatureisused(refertoGROUP
functionexplanationlaterinthissection).
5. PresstheBACKandthentheESCsoft‐keystoreturntothenormaloperatingmode.
OPTIONSMenu
1. PresstheLEFTbuttontoaccesstheprogrammingmenu
2. UsetheUP/DOWNbuttontoscrolldowntoOPTIONS
3. PressLEFTbuttontoselectOPTIONS
4. UsetheUPandDOWNbuttonstoscrolltotheMEASUREMODE,WORKINGMODE,PROBE
USED,UNITSETTINGS,BACKLIGHT,LCDSTATISTICS,ANDAUTOPOWEROFFparameters.Use
theLEFTsoft‐keytoselectthedesiredparameter.Eachparameterisdetailedbelow:
a. MeasureModes
SelectCONTINUOUSorSINGLEunderMEASUREMODESintheOPTIONSMenuusingthe
arrowbuttons.
IntheCONTINUOUSmeasurementmodethemeterdisplaysarunningaverageofreadingsas
theyaretaken.Notethattheaudiblemeasurement‘beep’isnotactiveinthismode.
IntheSINGLEmeasurementmodemeasurementsaretakenoneatatime.Singlemode
measurementreadingsareaccompaniedbyanaudibletone.
b. WorkingModes
SelectDIRECTorGROUP1,2,3,or4underWORKINGMODESintheOPTIONSMenuusing
thearrowbuttons.
InDIRECTmode,individualreadingsareloggedtomemory.Whenpowerisswitchedofforif
themeterisswitchedtoGROUPmode,allDIRECTreadingswillbecleared.However,the
statisticalanalysisdatawillremain.Thestatisticalanalysisutilitycanevaluateupto80
readings.Whenthememoryisfilled,newreadingswillreplaceoldreadings.Lastly,this
modehasitsowncalibrationandalarmlimitvalues.
InGROUPmodeeachgroupmemorycanstoreamaximumof80readingsand5statistical
values.Calibrationandalarmlimitvaluescanbeindividuallysetandstoredforeachgroup.
Whenthememoryisfilled,measurementswillcontinuetobetakenbutreadingswillno
longerlog(previouslyloggedreadingsarenotaffected);inaddition,statisticaldatawillno
longerupdate.Ifdesired,thegroupdata,statisticalvalues,calibrationdata,andalarmlimit
valuescanbedeletedusingtheprogrammingmenu.

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c. ProbeUsed
SelectAUTO,Fe,orNoFeunderPROBEUSEDintheOPTIONSMenuusingthearrowbuttons.
IntheAUTOmode,themeterautomaticallyactivatestheprobemeasurementmethod
(ferrousornon‐ferrous)basedonthemetalsubstratethatisbeingmeasured.Whenthe
probeisplacedonamagneticsubstrateitwillworkinthemagneticinductionmode.Ifthe
probeisplacedonanon‐ferrousmetalitwillworkintheeddycurrentmode.
IntheFerrous(Fe)ModetheMagneticinductionmeasurementmodeisactivated.
IntheNon‐Ferrous(NoFe)Modetheeddycurrentmeasurementmodeisactivated.
d. Unitsofmeasureselections
Selectmm,µmormilsunderUNITSETTINGintheOPTIONSMenuusingthearrowbuttons
(mm=millimeters;µm=micrometers;mils=mm*2.54/100)
e. Backlight
SelectONorOFFunderBACKLIGHTintheOPTIONSMenuusingthearrowbuttons.IfOFFis
selectedtheLCDbacklightingwillbecompletelydisabled.IfONisselected,theusercan
adjustthebrightnessofthebacklight.
f. LCDStatistics
SelectAVERAGE,MINIMUM,MAXIMUM,orSDEV(StandardDeviation)underLCDSTATISTICS
intheOPTIONSMenuusingthearrowbuttonsandtheSELECTsoft‐key.Thisselection
determineswhichstatisticisshownasdefaultontheLCDdisplay.
g. AutoPowerOFF
SelectENABLEorDISABLEunderAUTOPOWEROFFintheOPTIONSMenuusingthearrow
buttons.Whenenabled,themeterautomaticallyswitchesOFFafter10minutesofinactivity.
Whendisabled,themeterwillonlyswitchOFFwithabuttonpressorwhenthebattery
powerisweak.
h. BluetoothON/OFF
SelectONorOFFunderBluetoothintheOPTIONSMenuusingthearrowbuttons.IfOFFis
selectedtheBluetoothwillbecompletelydisabled.WhenBluetoothisONdatawillbe
automaticallysenttoPC,phone,orotherBluetoothreceivingdevice.
WhenthefirstconnectionisbeingmadethedevicemaypromptforaPINnumber.Inthis
caseentercode0000.
Note:TurnonBluetoothonlywhennecessaryasthebatterywilldrainmorequicklywith
BluetoothpoweredON.
i. Grayscalecontrast
PressLEFTbuttontoentermenumode.Usearrowbuttonstoadjustthegrayscaletodesired
contrast.

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DELETEMenu
TheDELETEmenusallowsfordeletingcurrentdata,alldata,andgroupdata.Thefollowing
parametersareavailableintheDELETEMenu:
DeleteCurrentdata:Deletescurrentreadingandupdatesthestatistics(AVG,MIN,MAX,etc.)
DeleteAlldata:Deleteallreadingandstatisticaldata.
DeleteGroupdata:Thisfunctionduplicatesthe“Deletealldata”functionwithadditional,
deletionsofHighalarm,Lowalarm,andone‐andtwo‐pointcalibrations.
1. PresstheLEFTbuttontoaccesstheprogrammingmenu.
2. UsertheDOWNARROWbuttontoscrolldowntoDELETE.
3. PressLEFTtoopentheDELETEfunction.
4. UsertheARROWkeystoscrolltoCURRENT,ALL,orGROUP.
5. PressLEFTagaintochooseCURRENT,ALL,orGROUP.
MEASUREMENTVIEWMenu
TheMeasurementViewmenuallowsforscrollingthroughthereadingsinallofthegroups.
1. PresstheLEFTbuttontoaccesstheprogrammingmenu.
2. UsertheDOWNARROWbuttontoscrolldowntoMEASUREMENTVIEW.
3. PressLEFTtoopentheMEASUREMENTVIEWparameter.
4. UsertheARROWbuttonstoscrollthroughthestoredreadings.
CALIBRATIONMenu
TheCalibrationmenuallowstheusertoenable/disablethecalibrationutility.TheCalibration
menualsoallowstheusertodeleteZerocalibrationdataforbothferrous(ZeroF)andnon‐
ferrous(ZeroN)modes.
1. PresstheLEFTbuttontoaccesstheprogrammingmenu.
2. UsetheDOWNbuttontoscrolldowntoCALIBRATION.
3. PressLEFTtoopentheCALIBRATIONparameter.
4. PressUP/DOWNtodeletezeropointofFeorNon‐Fe.
5. PressLEFTbuttonforOK
6. PressRIGHTbuttontoreturn.
MeasurementConsiderations
1. Aftercalibration,measurementsshouldmeetthepublishedaccuracyspecifications.
2. Strongmagneticfieldscanaffectthereadings.
3. Whenusingthestatisticalanalysisfunctionsforobtainingameanvalue,takeseveral
readingsofthesamemeasurementarea.Falsereadingsoroutlierscanthenberemoved
(deleted)usingtheprogrammingmenu.
4. Thefinalreadingisderivedfromastatisticalcalculationwithregardtothemeter’s
publishedaccuracyspecifications.

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Calibration
CalibrationTypes
Themeterisfactorycalibratedbeforeshipmenttothecustomer;howeverthecustomershould
performazerocalibrationandamulti‐pointcalibrationbeforeanycriticalmeasurementsare
taken.Thecalibrationoptionsarelistedbelow.Readthedescriptionforeachandselectthe
bestmatchforagivenapplication.
1. ZeroPointCalibration:Performbeforeeachmeasurementsession.
2. OnePointCalibration:Useforhighaccuracywithrepeatedtestsonaconstantcoating
thickness.
3. Multi‐PointCalibration:Useforhighaccuracywithinaknownrangeofcoatingthickness.
4. Calibrationforshot‐blastedsurfaces.
CalibrationConsiderations
Thecalibrationsamplemustcorrespondtotheproductsampleinthefollowingways:
Curvatureradius
Substratematerialproperties
Substratethickness
Sizeofmeasurementarea
Thepointatwhichthecalibrationismadeonthecalibrationsamplemustalwaysbe
identicalwiththepointofmeasurementontheproductitself,especiallyinthecaseof
cornersandedgesofsmallparts.
Toachievethehighestmeasurementaccuracy,performseveralcalibrationsinsuccession(for
zerovaluesandcalibrationfilmvalues).
Preparingforcalibration
1. Cleantheprobetip(grease,oil,metalscrap,andtheslightestimpuritywillaffect
measurementanddistortreadings).
2. SwitchthemeterON(ata4”[10cm]minimumdistancefromanymetal).
3. Readythesuppliedmetalsubstratesamplesandnecessaryfilms(suppliedcalibration
referencefilms).
4. Themeterisnowreadyforcalibration.

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Zerocalibration
1. Placethemeteronanuncoatedsectionofthematerialtobe
measuredoronthereferencesubstrateprovided.Useeither
theFerrousorNon‐Ferrousreferenceasrequiredbythe
measurementapplication.
a. Placetheprobeontheuncoatedsubstrateandwatchthe
LCDreadings.
b. Whenthereadingsappearstable,liftthemeteroffthe
substrate
c. PresstheLEFTbuttontoentermenu
d. PressUP/DOWNbuttontoselectzero‐pointcalibration.
e. PressLEFTtoenterorRIGHTtoreturntomeasurementmode.
f. PressLEFTbuttontoconfirmcalibration.
2. PressandholdtheDOWNbuttontoenterzero‐pointcalibrationofFeinmeasuringmode.
3. PressandholdUPbuttontoenterzero‐pointcalibrationofNon‐Femeasuringmode.

DeleteFeorNon‐Fezero‐point
1. PressLEFTbuttontoentermenu
2. PressUP/DOWNbuttontoselectcalibration
3. PressLEFTbuttontoentercalibration
4. PressUP/DOWNtodeletezero‐pointofFeorNon‐Fe
5. PressLEFTtoselectOK
6. PressRIGHTtoreturntonormaloperatingmode.
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

StatisticalAnalysisConsiderations
Themetercalculatesstatisticsfromamaximumof80readings(ForGroup1throughGroup4,a
maximumof400readingscanbestored).NotethatreadingscannotbestoredwheninDIRECT
mode.However,statisticsonthesereadingscanstillbecalculated.Whenthemeterispowered
offoriftheworkingmodeischanged(intheprogrammingmenu),theDIRECTmodestatistics
willbelost.Thefollowingstatisticalvaluescanbecalculated:
NO.:Numberofreadings
AVG:Averagevalue
Sdev.:Standarddeviation(squarerootofadataset’svariance)
MAX:Maximumreading
MIN:Minimumreading

StatisticalTerms
Averagevalue(x)isthesumofreadingsdividedbythenumberofreadings.



StandardDeviation(Sdev)
Thesamplestandarddeviationisastatisticthatmeasureshowthesamplevalueis
distributedaroundthesamplemean.Thestandarddeviationofasetofnumbersistheroot
meansquareofthevarianceS2

Thevarianceofalististhesquareofthestandarddeviationofthelist,thatis,theaverageof
thesquaresofthedeviationsofthenumbersinthelistfromtheirmeandividedby
the(numberofreadings‐1)

Variance:S2=)1/()( 2
nxx 
Standarddeviation:S= 2
S

NOTE:
UsetheDELETEparameterfromtheprogrammingmenuimmediatelyafteranoutlieror
erraticreadinghasbeentaken.RefertotheDeletefunctioninProgrammingMenu.

StorageCapacityOverflow

InGROUPmode,ifthestoragecapacityisexceeded,statisticswillnotbeupdated,although
measurementscanstillbemade.Ifthememoryisfull,subsequentreadingswillnotbe
includedinthestatistics.Themeter’sdisplaywillshow“FULL”(intheSINGLEmeasurement
mode).
InDIRECTmode,whenthememoryisfull,thenewestreadingwillreplacetheoldestreading
andthestatisticswillbeupdated.
