BYK CAP 1000+ - Appendix B - Calibration Procedures; Appendix B: Verification of Calibration; Appendix B: Interpretation of Calibration Results

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Appendix B
APPENDIX B - CALIBRATION PROCEDURES
Normally there is no requirement to perform a cone calibration. Cones supplied at
the time of order are calibrated to the viscometer prior to shipment.
VERIFICATION OF CALIBRATION
At selected intervals, depending upon usage and number of operators, the CAP
ViscometercalibrationshouldbeveriedusingNISTFluids.ReferringtoAppendixA
(TableA-1),ndtheappropriateNISTFluid(s)forthecone(s)beingused.
With the viscometer set up, perform viscosity measurements following the outline
of Section III. Prior to pressing the RUN key to initiate a cone calibration, we
recommendaperiodofthermalequilibriumofapproximately30minutesfortheuid,
cone and plate. This period should begin immediately after entering the calibration
temperature and associated viscosity value (in cP). Execute viscosity measurement
and record results.
Verify the result to have an accuracy according to the information in Section III (Table
III-1). If the calibration is outside the accuracy limits, proceed with the following
Cone Calibration.
INTERPRETATION OF CALIBRATION TEST RESULTS:
When verifying the calibration of the CAP 1000+, the instrument and viscosity
standarduiderrormustbecombinedtocalculatethetotalallowableerror.
TheCAP1000+accuracyisdenedinSectionIII.1asafunctionofspindlenumber03.
BYK-Gardner Viscosity Standards Fluids are accurate to (+/-) 1% of their stated value.
EXAMPLE: Calculate the acceptable range of viscosity using CAP 1000+ with
Spindle 03 at 900 RPM; Standard Fluid CAP-3L with a viscosity of
350 cP at 25°C:
1) Calculate full scale viscosity range using the equation:
 FullScaleViscosityRange[P]=
Range Coefcient
RPM
 Where: RangeCoefcient=7500fromTable A2
Full Scale Viscosity Range
7500
=8.33 P (833 cP)
900
The viscometer is accurate to (+/-) 16.7 c P. (which is 2% of 833)
2) Theviscositystandarduidis350c P. Its accuracy is (+/-)1% of 350 or (+/-)3.5 cP.
3) Total allowable error is (16.7 + 3.5) c P. =(+/-)20.2c P. (0.2 P. ).
4) Therefore, any viscosity reading between 329.8 and 370.2 c P. indicates that the
viscometer is operating correctly. Any reading outside these limits may indicate
a viscometer problem. If the reading falls outside the acceptable range, perform
a cone calibration (Appendix B). If the calibration is outside the accuracy limits,
proceed with the following Cone Calibration.