Brookfield DV2T Extra Viscometer Manual do Utilizador descarregar pdf (Página 41)

Brookeld Engineering Labs., Inc. Page 41 Manual No. M13-167-B0614

AutoZero: AutoZero is an operation performed by the DV2T Viscometerautomatically

duringthepowerupsequence.Thisoperationsetstheinstrumenttransducer

toacorrectzerovalue.Thezerovalueshouldnotshiftovertime,however,

iftheuserdeterminesthatthezeroisnotcorrect,youcanforceanAutoZero

tobeperformedwithoutpoweringdowntheviscometer.WhentheAutoZero

functionisselected,theDV2TisimmediatelysettoAutoZeromodeandthe

userispresentedwiththeAutoZeroscreen(FigureII-2).Uponcompletion,the

userwillbereturnedtotheDeviceSetupmenu.

Oscillation Check: The Oscillation Check is a check of the performance of the lower

bearingoftheDV2TViscometer.ThislowerbearingiseitherPoint

andJewelorBallBearing.Correctperformanceofthelowerbearing

is essential for proper operation of the viscometer. A failed lower

bearingwillnormallycauseviscositymeasurementstobelowerthan

expected.

AnOscillationCheckisperformedasfollows:

• RemovethespindleandleveltheDV2TViscometer

• Gentlypushupontheviscometercoupling.

• Turnthecouplinguntilthe%Torquereadingis10–15%.

• Gentlyletgoofthecoupling.

• Watchthereading.The%Torquereadingshoulddecrease

smoothlyandoscillateabout0.0%.

SelectingOscillationCheckintheDeviceSetupmenuwillpresentthe

userrstwithascreeninstructingtoleveltheviscometerandremove

thespindle.Conrmationoflevelandspindleremovalwillpresentthe

userwiththeOscillationCheckscreenasshownbelow.

Figure IV-3

AsuccessfulOscillationCheckwillshowaverysmoothdecreaseof

%Torquewithanalvaluewithin+/-0.2of0.0.Anyvalueabove0.2%

orbelow-0.2%indicatesthatacalibrationcheckshouldbeperformed

(seeAppendixF).

TIP:HigherTorqueranges(HAandHB)willquicklyreturntothe

zerovaluewithoutdisplayingmuchoscillation.Thisisnormal

behavior.

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Brookfield DV2T Extra Viscometer Manual do Utilizador Página 41