HTC DM-85T User manual

DM-85TDIGTALMULTIMETEROperationManual
CONTENTS
GENERALDESCRIPTION……………………………
SAFETYPRECAUTIONS………………………………
FEATURES…………………………………………
OPERATIONINSTRUCTION…………………………
MAINTENANCE…………………………
TROUBLESHOOTING…………………………

1.GeneralDescription
Thisisa31/2 digitalmultimeterwithhighstablilityandperformance.ItusesaLCDwith
20mmhighfigure,whichmakesthereadingclearerandtheoperationmoreconvenient.
ItcantestDCV,ACV,DCA,ACA,resistance,capacitance,frequency,NCV,dutycycle,
temperature,diode,andcontinuity.Thismeteralsodesignedwithfunctionsincluding
unitsymboldisplay,datahold,lighting,autorange,autopoweroffandwarning
functions.Toassurehighaccuracyandresolution,itadoptsintegratedcircuit8‐bit
microprocessorandadualintegralA/DconversionasLCDdriver,givinghighresolution
andhighaccuracy.Itisanidealtoolforlabs,factoriesandradio‐technology.

2.SafetyInstructions
TheinstrumentisdesignedincompliancewithIEC1010standard(safetystandardissued
byInternationalElectrotechnicalCommittee).Pleasereadthefollowingsafety
instructionsbeforeoperation.

2.1Checktheconnectionandinsulationoftestleadstoavoidelectricshock.
2.2Toavoidelectricshockanddamagetothemeter,donotinputvoltageexceeding
ratedvalue.
2.3WhenmeasuringvoltagehigherthanDC60VorAC40V,pleasebecarefulandavoid
electricshock.
2.4Selectcorrectfunctionandrangetoavoidwrongoperation.
2.5Movethetestleadsawayfromtestpointswhenswitchingtootherfunction.
2.6Don’tinputvoltageincurrentterminal.
2.7Don’tmakeanymodificationtothecircuit.Itmaydamagethemeterorjeopardize
safety.
2.8Safetysymbols:
“”Highvoltage,“ ”GND,“ ”Dualinsulation,“ ”Refertomanual,“ ”Low
batteryindication.

3.Features
3.1GeneralCharacteristics
3.1.1Display:LCD;
3.1.2Maxdisplay:6000(35/6digits,automaticpolarity,andunitsymboldisplay);
3.1.3Measurementmethod:Analogtodigitalconverter(inmicroprocessorADC+MCU);
3.1.4Samplingrate:approx.3times/sec.
3.1.5Over‐rangedisplay:“OL”displayed.
3.1.6Lowbatteryindicator:“”
3.1.7Workingenvironment:(0～40) ,relativehumidity:<80%℃;
3.1.8Storecondition:(‐10～50) ,relativehumidity:<80%℃
3.1.9Battery:2pieces1.5Vbattery(“AAA”7#battery);
3.1.10Dimension:140×72×37mm(lengthxwidthxheight);
3.1.11Weight:approx.195g(includingbattery);
3.1.12Accessories:testleads,TP01thermocouple,usermanual,holster,giftbox,and
2*1.5Vbatteries.

3.2TechnicalFeatures
3.2.1Accuracy:±(a%×reading+digits).Toassureaccuracy,theambienttemperature
shouldbe(23±5)℃,relativehumidity<75%.Oneyearaccuracyisguaranteedsince
productiondate.

3.2.2DCVoltage（DCV）
RangeAccuracyResolution
600mV
±(0.5%+4)
0.1mV
6V1mV
60V10mV

600V±(1.0%+4)100mV
Inputimpedance:at200mvrange>40MΩ,atotherrangesis10MΩ.
Overloadprotection:600VDC/ACrms.

3.2.3.ACVoltage（ACV）
RangeAccuracyResolution
6V
±(0.8%+6)
1mV
60V10mV
600V±(1.0%+6)100mV
Inputimpedance:10MΩ.
Overloadprotection:600VDC/ACrms.
Frequencyresponse:at600Vrange:(40~1000)Hz,atotherranges:(40~2000)Hz
Displaying:TrueRMSresponse(calibrationbasedonsinewaveRMS)

3.2.4DCCurrent（DCA）
RangeAccuracyResolution
600uA
±(1.0%+5)
0.1μA
6000uA1μA
60mA10μA
600mA100μA
6A1mA
10A±(2.0%+5)10mA
Maximumvoltagedrop:200mVforfullrange.
Maximuminputcurrent:10A(within10seconds).
Overloadprotection:0.5A/250Vfuseand10A/250Vfuse.


3.2.5ACCurrent(ACA)

RangeAccuracyResolution
600uA
±(1.5%+5)
0.1μA
6000uA1μA
60mA10μA
600mA100μA
6A1mA
10A±(2.0%+10)10mA
Maximumvoltagedrop:200mVforfullrange.
Maximuminputcurrent:10A(within10seconds).
Overloadprotection:0.5A/250Vfuseand10A/250Vfuse.
Frequencyresponse:10Arange:40~100Hz,otherranges:40～400Hz.

3.2.6Resistance（Ω）
RangeAccuracyResolution
600Ω ±(0.8%+5)0.1Ω
6kΩ
±(0.8%+1)
1Ω
60kΩ 10Ω
600kΩ 100Ω
6MΩ 1kΩ
60MΩ ±(1.2%+5)10kΩ
Opencircuitvoltage:500mV
Overloadprotection:250VDC/ACpeakvalue.





3.2.7Capacitance(C)
RangeAccuracyResolution
60nF±(2.5%+6)10pF
600nF
±(2.5%+5)
100pF
6uF1nF
60uF10nF
600uF
±(5.0%+8)
100nF
6mF1uF
60mF10uF
Overloadprotection:250VDC/ACpeakvalue.

3.2.8Frequency
RangeAccuracyResolution
10Hz
±(0.5%+4)
0.01Hz
100Hz0.1Hz
1000Hz1Hz
10kHz10Hz
100kHz100Hz
1MHz1kHz
10MHz10kHz
Inputsensitivity:0.7Vrms.
Overloadprotection:250VDC/ACpeakvalue.

3.2.9DiodeandContinuityTest
MeasurementRangeTestconditions
 Diodeforwardvoltagedrop.
ForwardDCcurrentis
approx0.8mA,
reversevoltageis
approx2.2V.
Whentheresistanceundertest
islessthan50Ω,buzzersounds
continuously.
Opencircuitvoltage:
2.2V
Overloadprotection:250VDC/ACpeakvalue.
WARNING:Donotinputvoltageatthisrange!

3.2.10Temperature(℃/℉)
RangeAccuracyResolution
‐40℃~1000℃＜400 ±(℃1.0%+5)
≥400 ±(1.5%+15)℃1℃
0F~1832℉＜750 ±(℉1.0%+5)
≥750 ±(1.5%+15)℉℉
Thermocouple:Ktype.
WARNING:donotinputvoltageatthisrange!

Operation
4.1PanelDescription
①.LCD:Displaythedataandunitsymbol

NumberFeatureDescription
1 △ Relative (REL) mode is active
2 DataHoldisactive.
3 - Indicatesnegativereadings.
4 DC DCvoltageorcurrentmeasurement.
5 AC ACvoltageorcurrentmeasurement.
6 AUTO Autorangemode.
7 Null
8 Diodetestmode.
9 Thecontinuitybeeperison.
10 MAX MIN Null
11 APO Autopoweroffsymbol.
12 Thesymbolofhighvoltageriskindication.

13 Lowbatteryindication.Warning:Toavoiderror readings,whichcouldleadto
possibleelectricshockorpersonalinjury,pleasereplacethebatteryintime.
14
hFE
%，， ℃℉
MΩ，kΩ，Ω
Hz，kHz，MHz
mV, V
uA， mA， A
Null;
Null;
Dutycycle,DegreesCelsius,DegreesFahrenheit;
Megohm,Kilohm,Ohm;
Hertz,Kilohertz,Megahertz;
Millivolts,Volts;
Microamp,Milliamp,Amperes(A).


②.Rotaryswitch:itisusedtochangetherangeandchoosefunctions.
Switch
positionDescription
ACvoltagemeasurement.PressSELECTkeytoswitchbetweenfrequency/dutycycle
measurements.
DCvoltagemeasurement.
Ω Resistancemeasurement.
Diode/continuitymeasurement.PressSELECTkeytochoosediodeorcontinuityrange.
Capacitancemeasurement.
Hz Frequencymeasurement,PressSELECTkeytoswitchbetweenfrequency/dutycycle
measurements.
℃/℉ Temperaturemeasurement,pressSELECTkeytochoose℃or℉.
NCV Non‐contactvoltagedetector.
DCcurrentmeasurement(from0uAto6000uA).PressSELECTkeytoswitchtoAC
currentmeasurement(from0uAto6000uA).
DCcurrentmeasurement(from0mAto600mA).PressSELECTkeytoswitchtoAC
currentmeasurement(from0mAto600mA).
DCcurrentmeasurement(from0Ato10A).PressSELECTkeytoswitchtoACcurrent
measurement(from0Ato10A).

③InputTerminal
TerminalDescription
AInputterminalforACandDCcurrentfrom0to10.00A(Overloadformax10seconds).
VΩmA
Inputterminalforvoltage,resistance,diode,andcontinuity,andtemperaturepositive
(+)terminal.ACandDCcurrentfrom0uAto600mA(Max18hoursforlessthan
600mA).
COMCommonterminalforallmeasurements,andtemperaturenegative(‐)terminal.

④FunctionKey
SELECT/ Key:
1) Selectfunction:PressSELECTkeytochooseDCorACmeasurementunder
ranges.Under(Diode/Continuity)range,pressSELECTkeycanchoose
(diodetest)or  (continuitytest).Undertemperatureranges,pressSELECTkeyto
chooseDegreesCelsiusorDegreesFahrenheit.UnderACVranges,pressSELECTkey
toswitchbetweenFrequencyorDutyCyclemeasurement.
2) Whenthereisnomeasurementin15minutes,themeterwillautomaticallypower
offandentersleepmode.Oneminutebeforesleepmode,thebuzzerwillbeepfor5
timestoreminduser.Pressanybuttonorturntherotaryswitchwillexitthesleep
mode.
3) PressSELECTkeytoactivethemeterfromthesleepmodeorholdtheSELECTkey
downwhenturnonthemetertocancelautopowerofffunction.
4) TORCHFUNCTIONKey:PressTORCHFUNCTIONkeyformorethan2secondstoturn
onthetorch.Ppressitformorethan2secondsonceagaintoturnoffthetorch.

RANGE/RELKey
1) Autorangeisthedefaultwhenyouturnonthemeter,andthemeterdisplays
“AUTO”symbol.PressRANGEtoentermanualrangemode.PressRANGEtoswitch
betweentherangesavailablefortheselectedfunction.HoldtheRANGEbutton
downformorethan2secondstoreturntoautoranging,
2) Undercapacitancemeasurement,pressRELkeytoenterrelativevaluetestmode.
Thedisplayiszeroed,and△symbolappears.PressRELkeyagaintoexitrelative
valuetestmode.

HOLD/ LightKey
1) HOLDKey:PressHOLDkeytoenterHOLDmode.Thecurrentvaluewillbehold,and
symbol““willbedisplayed.PressHOLDagaintoexittheHOLDmode.
2) LightKey:PressHOLDkeyformorethan2secondstoturnonthebacklight.The
backlightcanlastfor15seconds.During15seconds,press“”lightkeyfor2
secondsagaintoturnoffthebacklight.

⑤Non‐contactvoltagedetectorarea.

AUTOPOWER OFF
T
R
U
E
R
M
S
M U
L
T
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⑥Holster,Batterydoor.
Seepicture.

4.2DCVmeasurement
4.2.1Inserttheblacktestleadinto“COM”terminal,andtheredoneinto“VΩmA”
terminal.
4.2.2Turntherotarytoswitchto“”ranges.UnderAutoRangestatus,itwilldisplay
“AUTO”symbol.Press“RANGE/REL”keycanchangetoManualrange,theavailable
rangesare600mV,6V,60V,600V.
4.2.3Connecttestleadstothetestpoint;LCDwilldisplaypolarityandvoltageofthetest
pointconnectedbytheredtestlead.
NOTE:
1) IfLCDdisplay“OL”undermanualrange,itmeansitisoverrange,nowyouneedto
selectahigherrange.
1) Donotinputvoltageover600V.Oritmaycausedamagetothecircuitofthemeter,
andthebuilt‐inbuzzerwillalarm.
2) Becarefulwhilemeasuringahighvoltagecircuit.DONOTtouchthehighvoltage
circuit.

4.3ACVmeasurement
4.3.1Inserttheblacktestleadinto“COM”terminal,andtheredoneinto“VΩmA”
terminal.
4.3.2Turntherotarytoswitchto“”ranges.UnderAutoRangestatus,itwilldisplay
“AUTO”symbol.Press“RANGE/REL”keycanchangetoManualrange,theavailable
rangesare600mV,6V,60V,600V;Press“SELECT”keytoswitchbetween
Frequency/Dutycyclemeasurement.
4.3.3Connecttestleadstothetestpoint;LCDwilldisplayvoltageofthetestpoint
connectedbythetestleads.
NOTE:
2) IfLCDdisplay“OL”undermanualrange,itmeansitisoverrange,nowyouneedto
selectahigherrange.
1) Donotinputavoltageover600V.Oritmaycausedamagetothecircuitofthe
meter,andthebuilt‐inbuzzerwillalarm.
2) Becarefulwhilemeasuringahighvoltagecircuit.DONOTtouchthehighvoltage
circuit.

4.4DCAmeasurement
4.4.1Inserttheblacktestleadinto“COM”terminalandtheredoneinto“VΩmA”
terminal(Max.600mA)orinto“10A”terminal(Max.10A);
4.4.2TurntherotaryswitchtoCurrentranges,autorangeisthedefaultwhenyouturn
onthemeter,“AUTO”symboldisplayed.Press“RANGE/REL”keycanchangetoManual
range,theavailablerangesare600uA,6000uA,60mA,600mA,6A,10A.
4.4.3Connecttestleadstothetestedcircuit;LCDwilldisplaypolarityandcurrentofthe
testpointconnectedbytheredtestlead.
NOTE:
1) Ifyouarenotsureabouttherangeofcurrentundertest,pleaseselectthehighest
range,andthenselecttheproperrangebasedondisplayingvalue.
2) IftheLCDdisplays“OL”,itmeansthecurrentisoverrange.Nowyouneedtoselect
ahigherrange.
3) Maximuminputcurrentis600mAor10A(subjecttowhichterminaltheredtest
leadisinsertedinto).Currentexceedingratedvaluewilldamagethefuse,andmay
causedamagetothecircuitofmeter.

4.5ACAmeasurement
4.5.1Inserttheblacktestleadinto“COM”terminalandtheredoneinto“VΩmA”
terminal(Max.200mA)orinto“10A”terminal(Max.10A);
4.5.2Turntherotaryswitchtoapropercuttentrange.Press“SELECT/ ”keytoselect
theACmode,autorangeisthedefaultwhenyouturnonthemeter,“AUTO”symbol
displayed.Press“RANGE/REL”keycanchangetoManualrange,theavailablerangesare
600uA,6000uA,60mA,600mA,6A,10A.
4.5.3Connecttestleadstothetestedcircuit;LCDwilldisplaythecurrentofthetest
point.


NOTE:
1) Ifyouarenotsureabouttherangeofcurrentundertest,pleaseselectthehighest
range,andthenselecttheproperrangebasedondisplayingvalue.
2) IftheLCDdisplays“OL”,itmeansthecurrentisoverrange.Nowyouneedtoselect
ahigherrange.
3) Maximuminputcurrentis600mAor10A(whichterminaltheredtestleadis
insertedinto).Currentexceedingratedvaluewilldamagethefuse,andmaycause
damagetothecircuitofmeter.

4.6RESISTANCEmeasurement
4.6.1Inserttheblacktestleadinto“COM”terminalandtheredoneinto“VΩmA”
terminal;
4.6.2Turntherotaryswitchto“Ω”ranges,press“SELECT/ ”keytoselect“Ω”
mode.Connecttwotestleadsacrosstheresistorundertest;
4.6.3Autorangeisthedefaultwhenyouturnonthemeter,“AUTO”symboldisplayed.
Press“RANGE/REL”keycanchangetoManualrange,theavailablerangesare600Ω,6k
Ω,60kΩ,600kΩ,6MΩ,60MΩ.
NOTE:
1) Ifyouarenotsureabouttherangeofcurrentundertest,pleaseselectthehighest
range;
2) IfLCDdisplays“OL”,itmeansitisoverrange.Nowyouneedtoselectahigherrange.
Whenmeasuringvalueisover1MΩ,thereadingwilltakeafewsecondstobestable.
It’snormalforhighresistancemeasurement;
3) Wheninputterminalisinopencircuit,LCDwilldisplay“OL”;
4) Beforemeasuringinlineresistor,makesurethatthepowerisoffandallcapacitors
aredischargedcompletely;
5) Whenthereisbigerror,itmaybeaffectedbyotheronlinecomponentorthereis
voltageontheresistor;
6) Donotinputanyvoltageatresistancerange.

4.7CAPACITANCEMEASUREMENT
4.7.1Inserttheblacklestleadin“COM”terminalandtheredonein“VΩmA”terminal;
4.7.2Turntherotarytoswitchto“ ”range;
4.7.3IftheLCDdoesn’tdisplay“0”,press“RANGE/REL”toclearthereading;
4.7.4Connectthecapacitorto“COM”and“VΩmA”terminal.(Note:theredtestleadsis
forpositivepole+).LCDdisplayscapacitancevalue.
NOTE:
1) Don’tinputvoltageorcurrentundercapacitanceranges;
2) Press“RANGE/REL”toclearthereadingbeforetestingtoassuretheaccuracy;
3) Thereisonlytheautorangemodeunderthecapacitancerange;
4) Thecapacitormustbecompletelydischargedbeforetestingtoavoiddamagethe
meter,;
5) Thereadingofahigherthan600uFrangewilltakemoreseveralsecondstobe
stabled.

4.8FREQUENCYMEASUREMENT
4.8.1Insertthelestleadsorshieldedcableinto“COM”terminaland“VΩmA”terminal;
4.8.2Turntherotarytoswitchto“Hz”range,connectthetestleadsorshieldedcableto
thesignalsourceortheloadwhichistested(Itshouldover3Hz).
4.8.3Press“SELECT/ ”keytochoosefrequency/dutycyclemeasurement,LCDwill
displaythefrequencyordutycycleofthetestedsignalsource.
NOTE:
1) Thereisonlytheautorangemodeunderthefrequencyrange;
2) Whentheinputishigherthan10VACrms,pleaseswitchtorangeandthen
selectfrequencyordutycycletomeasure;
3) Innoisyenvironment,it'sbettertouseshieldcabletomeasurealowsignal;
4) Donottouchthehighvoltagecircuitwhenmeasuringhighvoltagecircuit;
5) Don’tinputvoltagehigherthan250VDC/ACpeakvalueunderHzranges,oritmay
damagethemeter.

4.9NON‐CONTACTVOLTAGE(NCV)DETECT

WARNING:
Thisfunctioncouldbeaffectedbydifferentexternalinterferencesources,andthenthe
alarmisactivatedbywrongsignal.Themeasurementresultisforreferenceonly.

Turntherotaryfunctionswitchto“NCV”position.Whenthetestingcircuitisplaced
abovethemeter,themeterdisplaysthestrengthofsignal,andthebuzzeralarmswith
“beepbeep”.
NOTE:
1) Evenifthereisnovoltageindication,theremaybevoltageonthecircuit.Donot
relyonNCVdetectorastheonlywaytodetectvoltage.
2) Voltagedetectingmaybeaffectedbypowersocketdesign,typeofinsulationandits
thicknessandotherfactors.
3) Interferencesourcesintheexternalenvironment,suchasflashinglight,motor,
wouldcausewrongsignaltoactivatealarmfunction.

4.10DIODEANDCONTINUITYTEST
4.10.1Inserttheblacktestleadinto“COM”terminalandtheredoneinto“VΩmA”
terminal(thepolarityofredleadis“+”);
4.10.2Turntherotaryswitchto“Ω”range,andpress“SELECT/ ”keytochoose
“”mode;
4.10.3Forwardmeasurement:connectredtestleadtothepositivepolarityandthe
blacktestleadtothenegativepolarityofthediode.LCDwilldisplaytheapprox.valueof
forwardvoltagedrop;
4.10.4Backwardmeasurement:connectredtestleadtothenegativepolarityandthe
blacktestleadtopositivepolarityofthediode.LCDwilldisplay“OL”;
4.10.5Thecompletediodetestincludesforwardandbackwardmeasurement,ifthe
resultdoesn’tmeetthedescriptionsabove;itmeansthediodeisbroken;
4.10.6Press“SELECT/ ”keytoselectthecontinyitymeasurementmode;
4.10.7Connecttestleadstotwopointsoftestedcircuit,iftheresistanceislessthan50
Ω,thebuilt‐inbuzzersounds.
NOTE:
1) DONOTinputvoltageat“Ω”range.
2) Whentestcircuits,makesurethepowerisoffandallcapacitorsaredischarged.Any
negativepotentialorACsignalwillactivatethebuzzer.

4.11TEMPERATUREMEASUREMENT
4.11.1Turntherotaryswitchto“℃/℉”range.Press“SELECT/ ”keytoselect℃or
℉mode.
4.11.2Insertthecoldend(freeend)ofthermocouplein“VΩmA(+)”and“COM(‐)”
terminal,andputtheworkingend(temperaturemeasuringend)ofthermocoupleonthe
surfaceorinsidethetestedobject.ThenLCDwilldisplaythetemperatureoftested
object,andthereadingisin℃/℉(whenthepolarityiscontrary.Thereadingwill
decreasewhenthetemperatureofthetestedobjectincrease).
NOTE:
1) Whentheinputterminalisopencircuit,itwilldisplaytheenvironment
temperature.
2) Toensuremeasureaccuracy,donotreplacethetemperatureprobeunlessitis
necessary.
3) Donotinputvoltageattemperaturerange.

5.MAINTENANCE
Thismeterisapreciseinstrument.Anymodificationtothecircuitisnotallowed.
NOTE:
1) Don’tinputthevoltagevaluehigherthan600VDCorACrms.
2) Don’tinputvoltageatcurrent,resistance,diodeorcontinuityrange.
3) Don’tmakeanymeasurementswhenthebatteryisnotproperlyinstalledorthe
backcoverisn’tfixed.
4) Beforereplacingbatteryorfuse,pleaseremovethetestleadsfromthemeasuring
pointandturnoffthepower.
5) Keepthemeterawayfromwater,dustandshock.
6) Don'texposethemeterunderhightemperature,highhumidity,combustible,
explosiveandstrongmagneticplace.

7) Wipethecasewithadampclothanddetergent.Donotuseabrasivesandalcoholto
cleanthemeter.
8) Ifthemeterwillnotbeusedforalongtime,pleasetakeoutthebatterytoavoid
leakagedamage.
9) When“ ”symbolisdisplayed,pleasereplacethebatteryaccordingtothe
followingsteps:
①Removetheholsteratfirst.
②Screwoffthefixingscrewsofthebatterydoorandremovethecover;
③Takeofftheoldbatteryandreplacewithanewone.Toextendtheusinglife,
it'sbettertousealkalinebattery.
④Fixthebatterydoor.
⑤Putontheholster.
10) Fusereplacement:Whenreplacingfuse,pleaseusefusewithsametypeand
specification.
①Removetheholsterfirst,thenscrewoffthefixingscrewsofthebatterydoor
andbackcovertoremovethecover;
②Takeofftheoldfuseandreplacewithanewone.
③Installthebackcover,thenfixthescrewsofthebatterydoorandbackcover.
Putontheholster.

6.TroubleShooting
Ifthemeterdoesnotworkproperly,pleasecheckthemeterasfollowingsteps:
(Iftheproblemsstillcannotbesolved,pleaserefertorepairingcenterorcontactthe
localdealers.)

FatultSolution
NoreadingonLCD
Turnonthepower;
ReleasetheHOLDkey;
Replacebattery.
signalappearsReplacebattery.
NoinputReplacefuse.
BigerrorValueReplacebattery.

● Thespecificationsaresubjecttochangeswithoutpriornotice;
● Thecontentofthismanualisregardedascorrect.Ifusersfindoutanymistakesor
omissions,pleasekindlycontactthemanufacturer;
● Themanufacturerwillnotberesponsibleforaccidentsanddamagecausedby
improperoperations;
● ThefunctionsdescribedinthisUserManualshallnotbeconsideredasthereason
foranyspecialusages;

