Balance for calibrating pipettes
A balance including a weighing chamber ( 16 ); a draft shield ( 23 ), which surrounds the weighing chamber; a climate module ( 34 ), which is detachably disposed in the weighing chamber; a processor ( 32 ), which is programmed to provide an evaporation rate correction value; a data input unit; and a data transmission path, over which data is exchanged between the climate module and the processor. Also disclosed are a climate module configured to electrically yet detachably couple to a balance, wherein the climate module forms a self-contained modular unit and includes various sensors ( 52, 54, 62 ) and a path over which data is transmitted to an external processor, and to a method for calibrating a pipette using a balance, wherein an evaporation rate is determined during the calibration process, and the measurement is corrected in accordance with the determined evaporation rate.
1. Balance for calibrating pipettes, comprising:
a draft shield, which delimits a weighing chamber;
a climate module, which comprises an air pressure sensor, an air humidity sensor and an air temperature sensor, and which is configured to mount detachably within the weighing chamber and is configured to detach without damage from the weighing chamber;
a processor which is configured to receive signals from the air pressure, the air humidity, and the air temperature sensors and is programmed to provide an evaporation rate correction value in accordance with the air pressure, the air humidity, and the air temperature signals;
a data input unit; and
a data transmission path, over which data comprising the air pressure, the air humidity, and the air temperature signals is exchanged between the climate module and the processor.
2. The balance as claimed in claim 1 , wherein the processor provides the evaporation rate correction value from an evaporation rate correction table or computes the evaporation rate correction value.
3. The balance as claimed in claim 1 , wherein the data transmission path comprises an electrical plug-in connection.
4. The balance as claimed in claim 1 , further comprising a sensor configured to determine a degree of ionization in the weighing chamber as a further signal exchanged between the climate module and the processor over the data transmission path.
5. The balance as claimed in claim 1 , further comprising a light sensor arranged in the weighing chamber and configured to determine a light intensity in the weighing chamber, and to output an additional signal over the data transmission path.
6. The balance as claimed in claim 1 , wherein the processor is programmed to determine a measurement uncertainty, based on climate parameters in the weighing chamber.
7. The balance as claimed in claim 1 , further comprising an evaporation trap disposed inside the draft shield.
8. The balance as claimed in claim 1 , wherein the data transmission path comprises a wireless transmission path.
9. Method for calibrating a pipette with a balance that comprises a draft shield that delimits a weighing chamber and separates the weighing chamber from a surrounding area, said method comprising:
mounting an air pressure sensor, an air humidity sensor, and an air temperature sensor within the weighing chamber, wherein the sensors are coupled to a processor for outputting a measurement,
determining an evaporation rate from calibration data during a calibration process, and
correcting the measurement as a function of the determined evaporation rate.
10. The method as claimed in claim 9 , further comprising selecting one of a plurality of predefined evaporation rates as a function of climate parameters provided by the sensors.
11. The method as claimed in claim 9 , further comprising computing an actual evaporation rate as a function of climate parameters provided by the sensors.
12. The method as claimed in claim 9 , further comprising:
recording climate values throughout the calibration process; and
modifying the determined evaporation rate once the climate values change by a predetermined amount.