6 Adjusting and Calibrating
20
C78IB007EN-B
on the viscosity range, on the used spindle, on tem-
perature stability and on the user’s repeatability.
Equipment
•
Reference standard liquid. Store such liquids in
their
closed
original containers in cool and dark
places. Check the expiry date.
•
For standard spindles:
600 mL lab (low Griffin) beaker
•
Pt100 temperature sensor, calibrated
(section 6.2.2)
•
Thermostat bath (stability ±0.1 °C)
•
Spindle, guard (if required)/measuring system
Remark: Silicone standards < 30,000 mPa·s are
recommended for 600 ml beaker.
TIP: Due to the small surface of the following spin-
dles they are not recommended for calibration: L4,
RH7. The reduced contact of liquid and spindle does
not allow for the required accuracy.
Preparation
Set the thermostat bath to the desired temperature.
Refer to section 4.2.3.5 for using a bath thermostat.
Fill the reference liquid into the sample vessel. Im-
merse the spindle (if in use: also the spindle guard)
in the sample. Place the Pt100 sensor in the sample
vessel. Mount the parts as described in section 5.3
and section 4.2.3.1. Place the sample vessel into
the thermostat bath. Wait for temperature equilibri-
um. The displayed temperature must be stable
(±0.1 °C) before you start measuring. Let the spin-
dle rotate at slow speed for better temperature dis-
tribution.
TIP: If using a standard spindle that requires
500 mL of reference liquid, wait for at least one hour
(from the moment the bath thermostat has reached
the set temperature).
Spindle L1 requires more than 500 mL filling vol-
ume, or place the beaker in a higher position (e.g.
on a lab boy).
Calibration
It is recommended to use "TruMode" in method
"Stop at Time (@t)", target time 60 s. Start measur-
ing. Note down the result and determine the devia-
tion from the reference value.
Determining the allowed deviation
The allowed deviation is the total of the lab repeat-
ability plus the accuracy of the ViscoQC model (1 %
of full scale range, see table 7) plus the uncertainty
of the reference standard (see certificate).
If the calibration result exceeds the allowed devia-
tion, calculate a new spindle correction factor
(section 6.2.1)
6.2 Adjusting
Apart from Level Adjustment (section 4.2.2) and
Zero Adjustment (section 4.2.2), you can adjust the
following settings:
-
Edit Spindle Correction (section 6.2.1)
-
Edit Temperature Offset (section 6.2.2)
View adjustment data in the data memory. Select
"Menu > Data Memory > Adjustment Data". Select
the current adjustment report or the adjustment his-
tory, which traces all adjustments (including
TruSine™ bearing checks) performed on this instru-
ment.
Spindle correction factors are not listed, be-
cause they are stored on the Toolmaster™ chip of
the spindle
. You can print, export or delete adjust-
ment data.
6.2.1 Setting Spindle Corrections
The
Spindle Correction Factor
(
SCF
) serves to ad-
just the results you obtain with a certain ViscoQC
setup to a (certified) reference value. This is neces-
sary if a calibration yields a deviation that is greater
than allowed (section 6.1).
The ViscoQC setup includes test speed, test tem-
perature, spindle, sample vessel, and (if applicable)
spindle guard.
TIP: You can also adjust the SCF if you do not use
the spindle guard for a spindle that requires it, or if
the size of your vessel is other than recommended.
The SCF is stored directly on the Toolmaster™
chip of the spindle
. It is a spindle-specific parame-
ter, not an instrument-specific one. Therefore, you
can edit the SCF only if the Toolmaster™ is enabled
(section 7.4.1.2).