Device for determining and/or monitoring the filing level of a medium

An apparatus for ascertaining and/or monitoring fill level of a medium, comprising:

• a plurality of piezoelectric sensors for producing and receiving ultrasonic signals;
• a scanning circuit for selective evaluation and selective driving of said plurality of piezoelectric sensors by means of at least one measurement transmitter;
• a signal evaluating unit in said measurement transmitter for ascertaining from the ultrasonic signals, on the basis of a travel time measuring method, the fill level of the medium;
• and
• at least one exciter switching circuit provided in said scanning circuit for each of said plurality of piezoelectric sensors to be driven, for selective driving of a selected one of said plurality of piezoelectric sensors for producing ultrasonic signals.