Principle of ultrasonic distance measurement sensor and high precision liquid level measurement system

Ultrasonic distance measurement has a series of advantages, but there are many factors that affect measurement accuracy, so it is difficult to achieve higher accuracy. Based on the principle of ultrasonic distance measurement, a single temperature ultrasonic transducer , humidity compensation scheme is single, and the defect that high-precision distance measurement cannot be achieved in a changeable and harsh environment, and a standard baffle compensation scheme for double ultrasonic transducers The cost is high and cannot be widely used in various fields. A single ultrasonic transducer standard baffle compensation scheme is designed that uses a steering gear to control the direction of the ultrasonic transducer. In response to the requirement that the first echo front cannot be accurately captured, a programmable gain amplifier is proposed to capture the return front of the echo at different distances. The experimental results show that in the range of 7 m, when air is used as the propagation medium and the reflective surface is water with good emission properties, the measurement error is controlled within 0.4%. This improved method can achieve low-cost under the harsh and changeable environment. 

High-precision ranging.

At present, there are many methods of liquid level measurement, such as float level measurement, input pressure-assisted level measurement, microwave radar level measurement, infrared level measurement, laser level measurement and ultrasonic level measurement. Among them, the pressure sensor represented by contact measurement will be contaminated when used in scenes such as heavy sediment, and then cause large errors. For non-contact ranging systems, the realization of ultrasonic transducer sensor is technically difficult and costly; infrared liquid level measurement is low in cost and easy to implement, but has poor directivity and low accuracy; while ultrasonic liquid level measurement can be done without contacting the liquid surface avoids the influence of liquid pollution and corrosion on the measuring equipment, and is not subject to light, smoke, electromagnetic interference, and has the advantages of high resolution, simple system structure, convenient installation, and low cost.

Ultrasonic distance measurement methods mainly include phase detection method, acoustic wave amplitude detection method and transit time detection method. Although the phase detection method has high accuracy, the measurement range is limited, so it is less applied; the acoustic wave amplitude detection method has low accuracy and is easily affected by reflected waves; while the transit time method is between the first two methods, with higher accuracy and measurement,It has a wide range and is widely used.

In practical applications, the design of the ranging system has a great influence on the ranging accuracy. Therefore, analyzing the working principle and process of ultrasonic ranging, improving the methods and methods of ranging, and improving the accuracy of ultrasonic ranging has attracted more and more attention. According to the specific environment of the ranging system, the method of improving the accuracy is slightly different. This article focuses on reducing the influence of the external environment, the choice of ultrasonic level meter is combined with the realization of the specific system, to improve the accuracy of ultrasonic level measurement.