11 Checking, Adjusting and Calibrating the Instrument
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2. Activate the check box "Density Module" and tap <OK>.
11.4 Calibrating
The goal of a calibration is to validate the accuracy of the density measurement.
To calibrate the instrument, measure a certified standard liquid and compare the
result to the reference value indicated in the calibration certificate of the standard.
The physical properties (density, viscosity) of the liquid density standards should
be similar to those of the samples.
The frequency of calibrations with certified liquid density standards depends on
your requirements and judgment. Recommendation: 1 to 2 calibrations per year.
To perform a calibration
1. Perform a density check with water.
2. If necessary, carry out an air/water adjustment at 20 °C.
3. Thoroughly clean and dry the measuring cell.
4. Select a measuring method that is set to "20 °C" and "measurement finished
by equilibrium". For DMA 5000 M, use the setting "measurement finished by
equilibrium slow".
5. Open the bottle with the liquid density standard.
TIP
If your bottle with density standard has a septum, we recommend you pierce it
carefully with any clean, sharp tool and fill a Luer tip syringe with standard liquid
by pushing the tip into the hole of the septum, holding the bottle upside down and
slowly pulling the plunger.
6. Immediately after opening the bottle, inject the standard into the measuring
cell of your M series DMA.
7. Perform a measurement.
TIP
If you have enough standard liquid, we recommend making a series of three
measurements and take the arithmetic average of the results.
8. After the measurement is finished, print the result.
NOTICE
•
Always check the date of expiry of the calibration liquids.
•
Store the calibration liquids in a cool and dark place.
•
Use the calibration liquids immediately and only once after the container
has been opened.
