4 How the USH-9 works
The USH-9 is a sensor to measure distance contact-free. Ultrasonic pulses with a frequency of 50 kHz
are emitted from the sensor-head and are reflected at any surface. The reflected signal is then detec-
ted by the sensor and from the travelling-time of the pulses the distance to the surface is calculated.
illustrates the path of the ultrasonic signal.
The ultrasonic pulses received by the sensor head are filtered for interferences and disturbing reflec-
tions, e.g. from precipitation. This permits reliable and accurate level measurements even during rain
or snowfall, or when the snow is of very low density.
As the speed of sound depends on temperature, the USH-9 is equipped with an integrated Pt1000 air
temperature sensor to automatically correct the measured distance and snow depth.
With the integrated, intelligent signal processing and the automatic switching between standby- and
measurement-mode the power consumption can be minimized. With a 12-Ah battery the USH-9 can
be operated for approx. 24 days with one measurement per minute.
Figure 1
Ultrasonic signal of the USH-9 sensor
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Manual
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