Why there is dead zone in ultrasonic level measurement?

A dead zone in ultrasonic level measurement occurs because the ultrasonic sensor requires time to emit a pulse and then listen for the echo. During this period, it cannot detect any objects or changes in the level, creating a region where measurements are not possible. This dead zone is typically influenced by the sensor's design and the speed of sound in the measured medium, limiting the minimum distance from the sensor at which reliable readings can be obtained.