Method for measuring the capacitance or capacitance change of a capacitive sensor, particularly for detection of the oil level in an oil sump, whereby it is ensured that electrode deposits do not cause spurious level indications

摘要

Method for measuring the capacity or capacity change of a capacitive circuit element in which a capacitive pulse is applied to the component which generates a corresponding current pulse that is detected in a time delayed detection window. The duration (TS) of the detection window is independent of the frequency transmitted input capacitive pulse. An Independent claim is included for a method for determining the liquid level of a liquid filled reservoir, especially an oil sump or reservoir using an inventive measurement method. Provision of a current measurement detection window ensures that spurious signals resulting from depositions on the electrodes of measurement capacitors are not detected as these have a wider current pulse than that resulting from a capacitor element with oil between its electrode plates.