How Ultrasonic Position Transducer Works

   Ultrasonic position sensor adopts the principle of ultrasonic echo measurement. It uses different measurement technology to detect the distance between the sensor . The ultrasonic sensor with small angle and small blind area has the advantages of accurate measurement, no contact, waterproof, anti-corrosion and low cost. Mainly is used in the liquid level, material level, material level detection and so on. The basic principle of the ultrasonic positioning sensor is shown in the picture.

  The basic principle of the ultrasonic position sensor is the system sends out the ultrasonic pulse single from the transmitting sensor,which passes to the measuring object and then returns to the receiving sensor after reflection, it measures the required time for the ultrasonic pulse from transmitting to receiving, and then according to the speed of sound in the medium, Getting the distance sensor from the measured object to determine the location. Taking into account the influence of ambient temperature on the ultrasonic propagation speed, the propagation speed of
transducer for flowmeter is corrected by a temperature compensation method to improve the measurement accuracy. The formula is:

S= vt
z = v(t1-t0)
z

  Where: S is the measured distance; T is the time difference between transmitting ultrasonic pulse and receiving its echo; t1 is the ultrasonic echo receiving time; t0 is the ultrasonic pulse transmitting time. Using the capture function of the MCU, it is convenient to measure the time t1 and the time t0. According to the formula, the measured distance S can be obtained by software programming.

   As shown in the figure, it is the ultrasonic fuel tank sensor indicating circuit. The circuit consists of an ultrasonic transmitting circuit and a receiving circuit. The ultrasonic transmitter circuit consists of NE555, R1, W1, C1 and ultrasonic transmitter UCM40T. The ultrasonic receiving circuit transducer consists of a receiving head UCM40R, a cascade amplifier BG1 and BG2, and a detection circuit that are matched with the transmitting head. When the liquid level sensor approaches the receiving head, the deflection angle of the voltmeter increases, and the closer is the liquid surface , the larger corresponding is deflection angle. Thereby 2MHz ultrasonic sensor is realizing the detection liquid bit change function.

  Ultrasonic position sensors have many advantages over other sensors. Such as: ultrasonic oil level sensor is without any mechanical transmission parts, it do not touch the measuring object and non-contact measurement, it is not afraid of electromagnetic interference, ultrasonic flowmeter transducer is not afraid of strong corrosive liquids such as acid and alkali, so the performance is stable, reliable, long life. Its short response time makes it easy to implement real-time measurements without hysteresis. However, the current ultrasonic transmission sensors have some shortcomings, such as: reflection problems, noise problems, cross-cutting issues and so on. These problems can be solved by using a plurality of external ultrasonic flowmeter transducer is arranged at an angle, encoding the transmitted ultrasonic waves, and encoding the ultrasound signals emitted by each sensor.