Extech Instruments EX350 User manual

USERGUIDE
TrueRMSDigitalMultimeters
EX350Series

EX350TrueRMSDigitalMultimeter
EX355TrueRMSDigitalMultimeterwithTemperature




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TableofContents
1.INTRODUCTION3
2.SAFETYINFORMATION4
3.DESCRIPTIONS6
4.OPERATION9
PoweringtheMeter9
DisableAutoPowerOFF9
DisplayBacklight9
DataHold9
VoltageMeasurements10
10AAC/DCCurrentMeasurements12
mA/µAAC/DCCurrentMeasurements13
Non‐ContactVoltageDetector14
ResistanceMeasurements15
ContinuityMeasurements16
CapacitanceMeasurements16
LoZACVoltageMeasurements17
VariableFrequencyVoltageMeasurements17
DiodeTest18
TemperatureMeasurements(EX355only)19
Hzand%DutyCycleTest20
RelativeMode20
MaxMinMode20
5.MAINTENANCE21
6.SPECIFICATIONS22

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1. Introduction
ThankyouforselectingtheExtechEX350SeriesMeter.

TheEX350Seriesarefeature‐packedTrueRMSdigitalmultimeters.InadditiontostandardDMM
features,theyofferaLowImpedance(LoZ)mode,BacklitLCD,Non‐ContactVoltageDetector
thatsafelysenseselectricalsources,Variablefrequencyvoltagemeasurement,andTemperature
(EX355).

Thisdevice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,ProductRegistration,andCustomerSupport.

Features
6000count(EX355)or4000count(EX350)digitaldisplay
LargebacklitLEDdisplay
TrueRMSACVmeasurements
VariableFrequencyVoltagemeasurements
LoZmodeprotectsreadingsfromghostvoltages
AutoandManualRangemodes
0.5%DCVaccuracy
AutoPowerOFF(APO)withdisablefunction
Temperaturemeasurements(ModelEX355only)withincludedtemperatureprobe
10AAC/DCcurrentmeasurements
Non‐ContactVoltageDetector
Visualandaudiblecontinuitymeasurementalert
Lowbatteryindicator
CATIII600V

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

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2. SafetyInformation
Toensurethesafeoperationandserviceofthemeter,followtheseinstructionsclosely.Failureto
observewarningscanresultinsevereinjury.

WARNINGS
WARNINGSidentifyhazardousconditionsandactionsthatcouldcauseBODILYHARMorDEATH.
Whenhandlingtestleadsorprobes,keephandsandfingersbehindthefingerguardsatalltimes.
Removetestleadsfromthemeterbeforeopeningthebatterycompartmentormeterhousing.
UsethemeteronlyasspecifiedinthisUserGuideoraccompanyingQuickStarttoavoidcompromising
theprotectionsprovidedbythemeter.
Besuretousetheproperterminals,switchpositions,andrangeswhentakingmeasurements.
Verifythemeter’soperationbymeasuringaknownvoltage.Havethemeterservicedifthemeter
respondsunusuallyoriftherearequestionsregardingthemeter’sfunctionalintegrity.
Donotapplymorethantheratedvoltage,asmarkedonthemeter,betweenterminalsorbetweenany
terminalandearthground.
ReplaceblownfuseswithfusesofthesametypeandratingasspecifiedinthisUserGuide.
Usecautionworkingwithvoltagesabove30VACRMS,42VACpeak,or60VDC.Thesevoltagesposea
shockhazard.
Toavoidmisleadingreadingsthatcouldleadtoelectricshockandinjury,replacethebatteriesassoonas
thelowbatteryindicatorisdisplayed.
Disconnectpowertothecircuitundertestanddischargeallhigh‐voltagecapacitorsbeforetesting
resistance,continuity,diodes,orcapacitance.
Donotusethemeterinthepresenceofexplosivegasorvapor.
Toreduceriskoffireorelectricshock,donotusethemeterifitiswetanddonotexposethemeterto
moisture.
IndividualprotectiveequipmentshouldbeusedifHAZARDOUSLIVEpartsintheinstallationwhere
measurementsaretobecarriedoutcouldbeaccessible.

CAUTIONS
CAUTIONSidentifyconditionsandactionsthatcouldcauseDAMAGEtothemeterorequipment
undertest.Donotexposethemetertoextremesintemperatureorhighhumidity.
Disconnectthetestleadsfromthetestpointsbeforechangingthepositionofthefunction(rotary)
switch.
Donotexposethemetertoextremesintemperatureortohighhumidity.
Neversetthemetertotheresistance,diode,capacitance,orampfunctionswhenmeasuringthe
voltageofapowersupplycircuit;thiscouldresultinmeterdamageanddamagetotheequipment
undertest.

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SafetySymbolsthataretypicallymarkedonmetersandinstructions
Thissymbol,adjacenttoanothersymbol,indicatestheusermustrefertothe
manualoruserguideforfurtherinformation.
Riskofelectricalshock
Fusesymbol
Equipmentprotectedbydoubleorreinforcedinsulation
LowBatterysymbol
ConformstoEUdirectives
Donotdiscardthisproductinhouseholdtrash.
ACmeasurement
DCmeasurement
Earthground

PERIEC1010OVERVOLTAGEINSTALLATIONCATEGORY
OVERVOLTAGECATEGORYI
EquipmentofOVERVOLTAGECATEGORYIisequipmentforconnectiontocircuitsinwhichmeasuresare
takentolimitthetransientover‐voltagestoanappropriatelowlevel.
Note–Examplesincludeprotectedelectroniccircuits.
OVERVOLTAGECATEGORYII
EquipmentofOVERVOLTAGECATEGORYIIisenergy‐consumingequipmenttobesuppliedfromthefixed
installation.
Note–Examplesincludehousehold,office,andlaboratoryappliances.
OVERVOLTAGECATEGORYIII
EquipmentofOVERVOLTAGECATEGORYIIIisequipmentinfixedinstallations.
Note–Examplesincludeswitchesinthefixedinstallationandsomeequipmentforindustrialusewith
permanentconnectiontothefixedinstallation.
OVERVOLTAGECATEGORYIV
EquipmentofOVERVOLTAGECATEGORYIVisforuseattheoriginoftheinstallation.
Note–Examplesincludeelectricitymetersandprimaryover‐currentprotectionequipment

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3. Descriptions
MeterDescription(EX350pictured)
1. Non‐ContactVoltageDetectorandLED
2. LCDmulti‐functiondisplay
3. ManualRangebutton
4. Hz%button
5. ModeandLPFButton
6. Rotaryfunctionselectswitch
7. 10Ainputterminal
8. uAandmAinputterminal
9. Common(‐)inputterminal
10. Positiveinputterminal:Voltage,Resistance,Capacitance,Temperature(EX355),andµA
11. DataHoldandbacklightbutton
12. REL(RELATIVE)button
13. MAXMINbutton
*Batterycompartmentonbackofmeter


Fig3‐1METERDESCRIPTION



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DisplayIconDescriptions
Auto:Automaticrangemode
HOLD:Displayhold
:Relativemode
AC:AlternatingCurrentMeasurements
DC:DirectCurrentMeasurements
:Maindisplaydigits
A:Amperes(Current)
V:Volts(Voltage)
oC/oF:Temperatureunits
F:Farads(Capacitancemeasurementunits)
Hz:Hertz(Frequencymeasurementsunit)
%DutyCycle(AConly)
Ω(Ohms):Resistancemeasurementunit
LPFVariablefrequencyvoltagemode
:Batterystatusicon
‐Minus(negative)sign
MAX‐MINPeakMaximumandMinimumreadingmemory
:Diodemeasurementmode
:Continuitymodesymbol
AutoPowerOffenabled
Prefixes:µ(micro:10‐6),m(milli:10‐3),n(nano:10‐9),k(kilo:103),M(mega:106)

Fig3‐2METERDISPLAY





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Push‐ButtonDescriptions

PresstheM(MODE)buttontoperformthefollowing:
SwitchPositionMODE(M)ButtonFunction
(EX355)AC DC
AC DC
AC DC
Ω Ω  
TEMP(EX355)°C °F

PressandHoldLPFintheACVfunctiontoselectvariablefrequencytests.

PressR(Range)toswitchfromAutotoManualRange.HoldtoreturntoAutoRange.

PressactivatesRelative mode.

PresstoactivateMaxMinMode

PresstoturnHOLDon/off.PressandHoldtoturnbacklighton/off

PresstoselectHzor%inACVoltageorACCurrentmodes

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4. Operation
CAUTION:ReadandunderstandalloftheSafetystatementslistedinthesafetysection
ofthismanualpriortouse.
PoweringtheMeter
1. Turntherotaryfunctionswitchtoanypositiontopowerthemeter.Checkthebatteriesifthe
unitfailstopowerON.RefertotheMaintenancesectionforbatteryandfusereplacements.
2. TurnthefunctionswitchtotheOFFpositiontopowerOFFthemeter.
3. ThemeterhasanAutoPowerOFFfeature(APO)wherethemeterswitchesOFFafter15
minutesofinactivity.WhenAPOisenabled,theAPOicon willshowonthedisplaywhen
themeterispoweredON.TodisableAPO,refertothenextsection.
DisableAutoPowerOFF
ThemeterwillautopowerOFFafter15minutesofinactivity.Todefeatthisfeature,followthe
stepsbelow.
1. WiththemeterOFF,pressandholdtheM(MODE)buttonand,whilecontinuingtohold,turn
therotaryfunctionswitchtoanypositiontopowerONthemeter.
2. Themeterwillbeep5times.
3. Releasethebutton.
4. APOwillnowbedisableduntilthenextcycleofpower.
DisplayBacklight
WiththemeterpoweredON,pressandholdthebacklightbutton fortwosecondstoswitchthe
backlightONorOFF.Notethatexcessiveuseofthebacklightwillshortenthebatterylife.
Whenthepowersupplyvoltageofthebatteryfallsto2.6V,theLCDbacklightwillbefaintor
unusable;themeasurementfunctioncanbeusednormallyhowever.

DataHold
TofreezetheLCDmeterreading,presstheH(HOLD)button.Whiledataholdisactive,theH
displayiconappearsontheLCD.PresstheHbuttontoreturntonormaloperation.TheHiconwill
switchOFF.

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VoltageMeasurements
CAUTION:Whenconnectingthetestleadstothecircuitordeviceundertest,connectthe
blackleadbeforethered;whenremovingthetestleads,removetheredbeforetheblacklead.
Forsafety,besuretomeasureaknownvoltagebeforeusingtheinstrumentonan
unknowncircuit

ACVoltageMeasurements
1. Inserttheblacktestleadbananaplugintothenegative(COM)jackandtheredtestlead
bananaplugintothepositive(V/Ω)jack.
2. Turnthefunctionswitchtotheorthemposition.
3. PresstheMbuttontoselectACorDC(EX355only)
4. ThemeterdefaultstotheAutoRangemode(AutodisplayedonLCD).PresstheRbutton
toaccessthemanualrangemode.PresstheRbuttontostepthroughtheranges.Press
andholdtheRbuttontoreturntotheAutoRangemode(Autowillbedisplayed).
5. Touchthetestprobetipstothecircuitundertest.
6. Readthedigitalvalueofthemeasurementinthedisplay.Thedisplaywillalsoindicate
theproperdecimalpointandmeasurementtype/unitssymbols.
7. UsetheHz/%buttontoviewthefrequency(Hz)orthedutycycle(%)ofthemeasured
voltage


Fig4‐1ACVOLTAGEMEASUREMENTS
%DutyCycleNote:DutyCyclemeasurementsare
AConlyforthismeter.Measurementsignalsmust
be‘zerocrossing’andmustreach‐0.7Vforthe
metertoproperlydisplayDutyCycle%.