| 摘要 |
The invention relates to a method for measuring capacitance value CM of a capacitive sensor element using an integration method. A terminal of the sensor element is electrically connected to a first terminal of an integration capacitor with a known capacitance value CI, which is greater than the capacitance value CM of the sensor element, at a common circuit node, and a voltage UCI, which is applied to the integration capacitor, is measured by means of an A/D converter after a number IZ of executed integration cycles. The method according to the invention has the following method steps: a) setting a number N of integration cycles to be executed to a start value NStart and determining an end value NEnd for the number N of integration cycles to be executed, b) initializing a voltage sum value UGes to the value of null, c) initializing the number IZ of executed integration cycles to the value of null, d) carrying out the integration method until the number IZ of executed integration cycles has reached the number N of integration cycles to be executed, e) adding the voltage value UCI (N), which is determined in an ongoing manner by means of the A/D converter, to the voltage sum value UGes, f) increasing the number N by a value n, wherein n is greater than or equals 1 and is less than NDiff = NEnd - NStart, and repeating the method steps starting with step c) until the number N exceeds the determined end value NEnd, and g) interpreting the voltage sum value UGes as the measurement result. |
