Method for assessing the state of a sensor as well as sensor system and method for operating the sensor system

A sensor system, comprising:

• a sensor having a deflectable micromechanical sensor structure in the form of a suspended electrode and two fixed reference electrodes and two fixed measuring electrodes, wherein a capacitance of the measuring electrodes that is changed due to a change in pressure of a surrounding medium acting on the micromechanical sensor structure is detected and the suspended electrode is deflected via an excitation signal, wherein the micromechanical sensor structure is configured to detect a physical input variable and to convert the physical input variable into an electrical sensor signal, wherein a medium surrounds the sensor and directly or indirectly acts on the micromechanical sensor structure, and wherein the micromechanical sensor structure is deflectable using the excitation signal;
• a driver unit configured to generate and output the excitation signal, the excitation signal exhibiting at least an amplitude change;
• an evaluation unit configured to determine a response behavior of the micromechanical sensor structure in response to the excitation signal, and to form a measure of deviation based on a comparison of the response behavior with a reference behavior;
• and
• an assessment unit configured to assess a state of the sensor with respect to presence of a deposit, based on the measure of deviation.

A method for operating a sensor system, the sensor system including:

• (i) a sensor having a deflectable micromechanical sensor structure in the form of a suspended electrode and two fixed reference electrodes and two fixed measuring electrodes, wherein a capacitance of the measuring electrodes that is changed due to a change in pressure of a surrounding medium acting indirectly on the micromechanical sensor structure is detected and the suspended electrode is deflected via an excitation signal, wherein the micromechanical sensor structure is configured to detect a physical input variable and to convert the physical input variable into an electrical sensor signal, wherein a medium surrounds the sensor and directly or indirectly acts on the micromechanical sensor structure, and wherein the micromechanical sensor structure is deflectable using the excitation signal;
• (ii) a driver unit configured to generate and output the excitation signal, the excitation signal exhibiting at least an amplitude change;
• (iii) an evaluation unit configured to determine a response behavior of the micromechanical sensor structure in response to the excitation signal, and to form a measure of deviation based on a comparison of the response behavior with a reference behavior;
• and (iv) an assessment unit configured to assess a state of the sensor with respect to presence of a deposit, based on the measure of deviation, the method comprising the following steps:
• detecting, using the sensor system, a physical input variable, and converting, using the sensor system, the detected physical input variable into an electrical sensor signal;
• and
• performing, automatically at regular intervals and/or in an event-initiated manner and/or as initiated by a host system:
• generating the excitation signal using the driver unit,
• outputting the excitation signal to the micromechanical sensor structure,
• deflecting the micromechanical sensor structure using the excitation signal,
• detecting the response behavior of the micromechanical sensor structure in response to the excitation signal,
• comparing the response behavior to the reference behavior to determine the measure of deviation for the response behavior in relation to the reference behavior, and
• assessing, based on the measure of deviation, the state of the sensor with respect to the presence of the deposit.