METHOD FOR DETERMINING A FUNCTIONAL STATE OF AN ULTRASONIC SENSOR, WHEREIN A VOLTAGE IS SENSED, AND ULTRASONIC SENSOR DEVICE HAVING AN ULTRASONIC SENSOR

摘要

The invention relates to a method for determining a functional state of an ultrasonic sensor (5a) of an ultrasonic sensor device (5) for a motor vehicle (1). A sound transducer element (11) of the ultrasonic sensor (5a) is excited by means of an electrical test signal (P), the electrical test signal (P) being defined by an electrical current strength (I), a voltage (V) and a frequency (f), and the functional state is determined in dependence on an evaluation of the electrical test signal (P). The sound transducer element (11) is excited by means of an electrical test signal (P), which has a specified known electrical current strength (I) and is frequency-modulated, and a voltage (V) at the sound transducer element (11) is sensed, which voltage is dependent on said electrical test signal (P), and at least one value of a parameter that electrically characterizes the ultrasonic sensor (5a) is determined in dependence on the sensed voltage (V), which value is compared with a value of a reference parameter that electrically characterizes a reference ultrasonic sensor and the functional state of the ultrasonic sensor (5a) is determined in dependence on the comparison. The invention further relates to an ultrasonic sensor device (5).