PROCEDUREPR11-ONE-POINTPROCESSSENSOR
CALIBRATION
PURPOSE/SCOPE
Thisproceduredescribeshowtoperformaone-pointprocess
sensorcalibration.
PartsNone.
Tools•Externalinstrumenthavingthesametypeoftemperature
compensationasthetransmitter.
•Grabsampleofprocessliquid.
PROCEDURE
Theprocesssensorcalibratestatecontainstwocalibration
procedures:one-pointcalibrationandtwo-pointcalibration.
Thisprocedurecoverstheone-pointcalibration.
Aswiththecalibratestates,usetheNEXTsmartkeytotoggle
fromoneproceduretothenextthenselectthedesiredprocedure
usingtheSELECTsmartkey.UsetheexittoMEASURE
smartkeytoescapetothemeasuremode.
Theone-pointcalibratestateconductsanoffsetadjustmenton
thesensorinput.Usethiscalibrationprocedurewhenthesensor
isinthefinalinstalledlocation.Duetovariationsinionic
strengthbetweenthesensorreferenceandprocessliquid,
improvedaccuracycanberealizedbyconductingaone-point
calibrationwiththesensorinitsfinallocation.Thetransmitter
istypicallyverifiedagainstanexternalvalidationdeviceusing
agrabsample.
□1.Makesurethesensorisinitsfinalinstalledlocationand
orientation.
□2.Measuretheprocessvariablevalueusinganexternal
instrumenthavingthesametypeoftemperaturecompensation
asthetransmitterandagrabsample.
□3.Recordthevaluedisplayedonthetransmitteratthetime
thegrabsamplewastakenandthevaluedisplayedonthe
externalinstrument.
□4.PresstheNEXTsmartkeyuntilCALIBRATEishighlighted
onthedisplay.
□5.PresstheSELECTsmartkeytoenterthecalibratestate.
□6.PresstheNEXTsmartkeyuntil1PT.CALappearsonthe
display.
10min.
ONE-POINTPROCESSSENSORCALIBRATION
PROCEDURE
PR11-2WBPEEUI520002A1
□7.PresstheSELECTsmartkeytostarttheone-pointcalibration
procedure.
□8.ThetransmitterdisplaysSTABL?.Observethedisplayed
reading.Ifitisstable,presstheYESsmartkey.Ifitisnotstable,
presstheNOsmartkey.IfNOisselected,thetransmitter
returnstotheprocesssensorcalibrationstate.PerformSteps
9through11.IfYESisselected,gotoStep12.
□9.Waituntilprocessliquidcompositionstabilizes.
□10.Checktoseeifthetransmitterhasdetectedafaultcondition
bylookingfortheFAULTicononthedisplay.Interrogate
thefaultbyescapingtothemeasuremodethroughtheexitto
MEASUREsmartkeyandthenpressingtheFAULTinfosmart
keyinthatorder.
□11.RefertoPR53forinformationonerrorcodes.
□12.ThetransmitterdisplaysNEWVAL.
a.Calculatethenewprocessvariablevaluebysubtracting
thetransmittervaluerecordedinStep3fromtheexternal
instrumentvaluerecordedinStep3andthenadding
thatresulttothecurrentvaluedisplayedonthe
transmitter.
b.Usethesmartkeytoincrementthevalueofthe
blinkingdigit.
c.Whenthefirstdigitvalueiscorrect,usethesmart
keytomovetothenextdigit.
d.RepeatSteps12band12cforeachdigit.
e.PresstheENTERsmartkeytoacceptthenewvalue.
□13.Iftheenteredcalibrationvalueisnotvalid,thetransmitter
displaysBAD.CAL,andthecalibrationvalueisrejected.Ifthe
enteredcalibrationvalueisvalid,theslope(sensorefficiency)
appearsonthedisplay.PresstheNEXTsmartkeytodisplay
theoffset.
□14.PresstheNEXTsmartkeytoreturntotheprocesssensor
calibratestateorpresstheexittoMEASUREsmartkeytogoto
themeasuremode.
NOTE:Ifanoutputheldconditionispresent,thedisplayinquiresif
thisconditionshouldbereleased.
Moreinformationonsensorcalibrationtechniquesandtroubleshooting
iscontainedinCalibrationandTroubleshooting
ofpHLoops(Table1-1).