METHOD AND DEVICE FOR DETECTING PHASE BOUNDARIES AND CORRESPONDINGLY EQUIPPED LABORATORY DEVICE

摘要

The invention relates to devices (100) for detecting a phase boundary in a liquid tank (5.1 - 5.8). The device (100) comprises a sensor (3.1 - 3.8) that can be advanced in the direction of the phase boundary in the liquid tank (5.1 - 5.8). A circuit (13) is provided, which processes an output signal (s(t)) of the sensor (3.1 - 3.8), in order to detect a change in capacitance (dc/dt). The circuit (13) comprises a first channel having a first filter module in order to filter out a first signal (s1(t)), s1d) having a short pulse width from the output signal (s(t)), and a second channel (40) having a second filter module in order to filter out a second signal (s2(t), s2d) having a greater pulse width from the output signal (s(t)). A controller module (8) having a comparator module (11) is further utilized, which determines whether the first signal (s1(t), s1d) reaches a first threshold value. A processing module (12) is further provided, which determines whether the second signal (s2(t), s2d) meets predefined second signal criteria.