METHOD FOR MONITORING THE OPERATION OF A PRESSURE MEASURING CELL OF A CAPACITIVE PRESSURE SENSOR

摘要

The invention relates to a method for monitoring the function of a pressure measuring cell (10) of a capacItive pressure sensor (1), wherein the pressure measuring cell (10) comprises a pressure-dependent measuring capacitor (C_M) and a pressure-dependent reference capacitor (C_R) and the pressure measuring value (p) is obtained as a measuring signal from the capacitance values of the measuring capacitor (C_M) and the reference capacitor (C_R), wherein the measuring signal is supplied to an evaluation unit in the form of an alternating square-wave signal U_R, the pulse height of the signal depending on quotients of the capacitance values of the reference capacitor (C_M) and the measuring capacitor (C_M), wherein per period of the alternating square-wave signal U_R, the pulse height is measured at least twice during at least one pulse width, and the measured voltage values are stored in a memory (40), and wherein the at least two voltage values per pulse width are compared with each other in terms of the value thereof, and if they significantly deviate from each other, an error signal is generated.