Cannon Instrument CAV-2000 - Manual (Page 40)

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CANNON ® Automatic Viscometer Models CAV-2100 and CAV-2200 with VISCPRO ® Instruction & Operation Manual
Version 2g — May, 2009; CANNON ® Instrument Company
2139 High Tech Road • State College, PA 16803 • USA
information will remain in effect until the instrument is recalibrated at
that same temperature, or until instrument and tray settings from a
previously-saved instrument configuration are restored (see page 53).
To avoid losing valid calibration data, CANNON ® recommends saving
the instrument configuration settings after completing a new calibration
(see Saving a configuration, page 53). The name for the instrument
configuration should identify the specific instrument, the calibration
time, and the temperature:
EXAMPLE: CAV2 1-10-04 40C
After the instrument configuration has been saved, calibration data may
be restored at any time using the Restore Instrument Settings option
from the Configure menu (see page 53). Note that the Restore Instru-
ment Settings and Restore Tray Settings check boxes must both be
selected to restore instrument calibration data:
NOTE The Restore Instrument Settings and Restore Tray Settings options are
security-protected at the Manager level (see pages 37-39).
CAV calibration equations
Viscosity calculation equation In the CAV, viscosity is calculated by using the viscosity calculation
equations as described in ASTM Methods D 445 and D 446. Because
samples running in the CAV can have short flow times, the kinetic energy
correction term (E / t
2 ) is used as prescribed in the aforementioned ASTM
methods. The VISCPRO ® software for Windows ® performs all necessary
calculations to derive constants C and E. These constants are used by the
software when determining values for kinematic viscosity using sample
drop times measured by the CAV.
Kinematic Viscosity equation: v = C t - E / t 2
Where: v = kinematic viscosity (cSt)
C = calibration constant (cSt/s)
E = kinetic energy correction (cSt·s 2 )
t = flow time (seconds)
NOTE When calibrating the CAV, the operator must analyze the viscosity
standard using double determinations to obtain two flow times for each
standard. The average of the two flow times is used as input data for the
calibration program.