A&D Weighing FX-300i-PT - Manual (Page 24)

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9-3 Example Causes of Measurement Errors
Evaporation of the test liquid
Evaporation of the distilled water dispensed from the pipette into the sample cup can be a cause of
measurement error.
To reduce errors caused by evaporation
z Be sure to use the evaporation trap. Using the evaporation trap, evaporation of the test liquid can
be reduced to 0.05 mg per minute (0.05 μL per minute).
z With the AD-4212B-PT / AD-4212A-PT, use the display lock function. For details, refer to “10-2
Display Lock Function”.
Water temperature and barometric pressure
Correctness of the Z factor, that is used to convert a mass value to a volumetric value, depends on
the density by the water temperature.
The barometric pressure, even if changed in the range between 950 hPa and 1050 hPa, influences
measurements only by 0.01%.
Water temperature, if changed by 5°C, influences measurements by 0.11%.
To reduce errors caused by water temperature
z Use the correct Z factor. To obtain the correct Z factor, measure the water temperature using the
accessory thermometer and enter the value in WinCT-Pipette.
z For a stable water temperature, allow the temperature of the test liquid to acclimatize to the
measurement environment for an appropriate duration of time (ISO 8655 recommends two hours
or more) before measurement.
Vibration
Vibration yields unstable measurement values.
To reduce errors caused by vibration
z Install the balance in a stable place avoiding vibration and shock. Use a solid weighing table that is
free from vibration.
z If the installation site is the second floor or higher, use the AD-1685 anti-vibration table.