The ultrasonic level Transmitter is composed of an ultrasonic transducer(probe) emits high-frequency pulse sound waves, which are reflected back to the surface of the measured object (material), and the reflected echo is received by the transducer and converted into an electrical signal. The propagation time of the sound waves is proportional to the distance from the sound wave to the surface of the object. The time between the sound wave and the return sound wave is detected to calculate the distance from the sensor to the surface of the material, thereby calculating the height of the level.