Extech Instruments 341350A Manual

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341350A-EN V1.2 1/14

pHCalibration(1,2,or3points)

Atwopointcalibrationwithabufferof7plus4or10(whicheverisnearesttotheexpected

samplevalue)isalwaysrecommended.Aonepointcalibration(choosethevalueclosesttothe

expectedsamplevalue)orathreepointcalibrationisalsovalid.Forbestaccuracy,always

calibrateat

thesampletemperature.Frequencyofcalibrationisdependentonhowoftenthe

meterisused,careoftheelectrodeandstrengthofthesamplestested.Typically,itis

recommendedthatcalibrationbeperformedonceadayorbeforeeachuseifthemeterisnot

usedonadailybasis.

1. ConnectthepHprobeandplaceitintoapH7buffer.

2. PressthePOWERbuttontoturnthemeteronandpresstheMODE/CALbuttonuntilthePH

iconappears.(Note:disabletheAutoPowerOfffeaturetoavoidanautomaticpoweroff

duringcalibration)

3. IfMTCicon

appearsnexttothetemperaturedisplay,pressthe▼or▲buttonstosetthe

temperatureofthepHbuffer.Iftheoptionaltemperatureprobeisused,inserttheprobe

intothebuffersolution.

4. PressandHOLDtheMODE/CALbuttonuntilthedisplaybeginstoflash7.00.Themeter

automaticallyrecognizesthebufferandcalibratesitselftothatvalue.Attheendofthe

calibrationcycle,SAandEndwillbrieflyappearonthedisplayandthenthemeterreturns

tothenormaloperatingmode

5. Whenacalibrationisperformed,thecalibrationicons

(pH10) (pH7) (pH4)willbe

cleared(calibrationdataisnoterased)andwillbereplacedwhenasuccessfulcalibrationis

performedforeachbufferwithinonepoweroncycle.Theseiconsindicatewhatcalibration

levelswerelastperformed.Theydonotindicatehowrecentlythecalibrationwas

performedorifthecalibrationsare

stillvalid.

6. RemovetheelectrodefromthepH7buffer,rinseinarinsesolutionandinsertitintothe

pH4orpH10buffersolution.

7. Repeatstep4forthesecondcalibrationpointandthenthethirdpointifdesired.

Note:Iftheoutputoftheelectrodefallsoutside

predeterminedlimits,themeterwillcancel

thecalibration,indicateEndandtheRENEWiconwillflash.Thistypicallyhappenswhenthe

electrodehasagedandneedsreplacement.

Note:Toavoidcrosscontamination,alwaysrinsetheelectrodeinarinsesolutionwhen

changingfromonebufferorsampletothenextbuffer

orsample.