| 主权项 |
1. A method for the fill level control of a collecting vessel which is capable of being filled with a dielectric medium, wherein a fill level is monitored by means of a monitoring circuit comprising a measuring capacitor, the capacitance whereof steadily changes in correlation with the fill level at least over a fill level range of the collecting vessel, wherein the monitoring circuit comprises a switched capacitor element (SC element), which includes the measuring capacitor, at least one switching module and at least one ohmic resistor in series with the switching module, the method including the following steps:
ascertaining a capacitance of the measuring capacitor, changing an operating point or a circuit quality of the monitoring circuit by increasing the electrical resistance of the at least one ohmic resistor in series with the at least one switching module or by changing a pulse/pause ratio of a switching frequency for the SC element; ascertaining a quality factor of the measuring capacitor by determining the difference between output voltages of the monitoring circuit before and after the operating point or the circuit quality factor of the monitoring circuit is changed; determining a permittivity of the dielectric medium on a basis of the ascertained quality factor of the measuring capacitor, determining a fill level of the dielectric medium in the collecting vessel on a basis of the ascertained capacitance of the measuring capacitor and the permittivity of the dielectric medium,wherein
a fill level-dependent drainage of the dielectric medium from the collecting vessel is performed. |
