Ultrasonic distance sensors
A piezoceramic disk sends a short ultrasonic
air wave in the direction of the object whose
distance is to be measured. The sound wave
is reflected by this object and received
again by the same piezoceramic part. The
piezoceramic part thus operates here as
sender and receiver (time multiplex mode).
The piezoceramic part normally has a
adaption layer on the radiating side to
match the acoustic impedance of the transmitter
to that of the air. The frequency used by the
transmitter (resonance mode) here depends on
the desired range and on the resolution. The
higher the frequency, the higher the resolution
and the shorter the range, and vice versa. If
the wavelength resulting from the frequency is
large in comparison to the size of the transmitter,
the result is a spherical-shaped radiation of the
wave front. If the wavelength is shorter than the
transmitter, it is radiated straight (in a close angle). Directed
radiation is desired in almost all cases. The
distances which can reasonably be measured using
such systems are between 0.25 m and 10 m. This
application can be widely used in industrial
automation; such as e.g. for distance measurement,
as limit monitor or as a counter (an object is
registered every time it passes through).
Designs: Round disk
Material: SONOX® P5, SONOX® P508