Cannon Instrument CAV-2000 - Manual (Page 62)

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
56
Date selection: The calibration program uses data from previously-run
standards to determine the calibration constants. To select the desired
standard data, use the No older than [x] days spin controls to set the
date parameters for the database search (if “1” is selected, only the
standards run on yesterday and today’s date will be used).
NOTE Sample run data from at least two different standards for each bulb at
each calibration temperature must be available for calibration calcula-
tions to be performed.
Data selection: Test data from standards run with the CAV within the
specified Date parameter will be automatically displayed in the list box.
To select and deselect the data from the sample runs to be used for the
calibration, press and hold the C key and click on the samples to
highlight those you wish to include in calibration calculations (the default
is all selected). After you have selected the desired data, release the C
key and click Calculate new constants to update values for C and E:
Click on Calculate new constants to update
values for C and E.
You may evaluate the accuracy of the new calibration constants by
comparing the known viscosity for the standard with the calculated
viscosity for each standard selected for the new calibration. This differ-
ence is displayed as a percentage in the last column (% Diff) of the
updated sample list box.
Show Calibration Data
The Show Calibration Data button is a toggle that will
permit you to compare current and new calibration data and constant
information. Press the Show Calibration Data button once to view the
current calibration information. Note that the button name will change to
Display Sample Data. Press the button again to display the new calibra-
tion data.
When you are satisfied with calculation results,
click on Update bulb to save calibration values
for the current configuration.
If the difference is still too great, repeat the calibration process until the
difference falls within acceptable limits (refer to the precision statement
in ASTM D 445).
NOTES You must click Update bulb before changing to the next bulb if you wish
to save the new calibration constants for that bulb.
Once the Update bulb button is pressed, the updated calibration con-
stants are associated with the selected instrument, and will remain the
same regardless of the instrument configuration defined for that instru-
ment.