Patent ID: 8272263

Claim:
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, at least a first selection unit is provided in said scanning circuit, which operates and/or controls said exciter switching circuit selected via a selection input to said measurement transmitter; and at least a second selection unit is provided in said scanning circuit, which sequentially, selectively or cyclically, electrically connects, via said selection input, said piezoelectric sensors with said signal evaluation unit via a receiving path.