OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: 832-320-7300 / Fax: 713-880-9886 / www.ofite.com
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To zero the unit, loosen the bolts on the transducer housing and rotate
the hood slightly while observing the “Shear Stress Raw” value. When the
signal is within the acceptable range, tighten the bolts to secure the hood.
5.
Select a calibration fluid from the “Cal Fluid Batch” drop-down list. Open
the “Fluid Manager” and confirm that the settings match the data sheet
that was provided with the fluid.
If the list is empty, click the “Fluid Manager” button to add new fluid
batches. Refer to page 22 for more information.
If the “Temp Out of Range” light shines red, the current sample
temperature is out of the specified range for the calibration fluid. The
sample will have to be heated or cooled to be within the acceptable range
before calibration.
Do not attempt a calibration if the sample is not within the
appropriate temperature range.
6.
6. Choose a set of calibration rates from the “Rate Set”
drop-down list.
To create or edit a rate set, click the “Calibration Rates”
button. To create a new set, click the “New” button and
enter a name and the rotational speeds. To edit a set,
select it in the “Rate Set” list, then change the rotational
speeds as necessary.
Due to mechanical limitations, calibrating at shear rates lower than
10 RPM or higher than 300 RPM is very likely to provide poor results.
7.
Click the “Start Calibration” button to begin the calibration.
Once the calibration has started, the software will begin filling in the chart
and plotting the results on the graph.
8. As the calibration proceeds, the software will begin to display the
collected data in the chart. At the end of the calibration, the software will
calculate the “r^2” and “r^2C” values, which measures the accuracy of the
calibration. If “r^2C” is less than 0.9990, recalibrate the unit.
If this value is still low, remove the test cell and check the movement of
the rotor. The rotor should turn freely. If the unit still does not calibrate, it
will require servicing by an OFITE technician.
9.
When the calibration is complete, check the r^2C value to make sure it
is greater than .9990. If it is, click the “OK” button and enter a title for the
calibration.
Rate Sets
