The Echotel® Ultrasonic Non-Contact Transmitter (electronics) sends an electrical signal to the transducer sensor crystal, which causes the crystal to vibrate and emit an ultrasonic pulse. The sound pulse is directed toward the liquid surface where it is reflected as an echo back to the transducer, again causing it to vibrate. The electronics detects when the return echo is received, and converts the time interval into a distance.
Ultrasonic level measurement utilizes the simple equation D = Va t/2. The distance(D) is a function of the time(t) required for an ultrasonic pulse to travel at the speed of sound (Va) from the face of the transducer to the reflecting surface and back to the transducer. The instrument is, therefore, performing a timing function to determine the level.
The transducer is mounted above the maximum level of the media to be measured with the ultrasonic pulse directed at the surface of the media. As the level of the media moves, the time interval for the signal return also changes. The transmitter converts this time interval to a direct reading of level.
