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Unformatted text preview: ltrasonic beam
The ultrasonic sound wave beam can be diverted by means of even or slightly
concave reflectors, whereby objects can be detected "around the corner". 7.3.8 Effect of temperature of the object
Very hot objects, such as melting baths or red hot metal leads to strong air striation
and can interfere with ultrasonic propagation. Preliminary experiments are therefore
recommended. 7.3.9 Effect of ambient noise
As the transmission frequencies are in the range of 30 – 250 kHz and due to the
limited receiver bandwidth, ultrasonic proximity sensors are generally little affected
by external noise. In exceptional cases they may react to intensive, selective
interference. © Festo Didactic GmbH & Co. KG • FP 1110 115 7. Ultrasonic proximity sensors 7.4
Examples of application Ultrasonic proximity sensors are used for monitoring filling levels in silos.
Ultrasonic proximity sensors have also proved reliable for the control of automatic
trolleys in warehouses.
The following illustrations show a few additi...
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- Spring '12