Views:2 Author:Site Editor Publish Time: 2020-05-09 Origin:Site
The principle and structure of modern ultrasonic ranging sensors vary greatly. How to select a sensor reasonably according to the specific measurement purpose, measurement object and measurement environment is the first problem to be solved when performing a certain amount of measurement. After the ultrasonic sensor is determined, the matching measurement method and measurement equipment can be determined. The success or failure of the measurement results depends to a large extent on whether the choice of ultrasonic ranging sensors is reasonable. This article mainly introduces several parameters that are generally noticed when selecting an ultrasonic ranging sensor, for reference only.
1) Determine the type of ultrasonic sensor (hereinafter the sensor will replace the ultrasonic ranging sensor) according to the measurement object and measurement environment
To carry out a specific measurement work, we must first consider what principle is used to solve this problem, which needs to be determined after analyzing many factors. Because, even when measuring the same physical quantity, there are multiple principles of sensors to choose from, which principle of the sensor is more suitable, you need to consider the following specific issues according to the characteristics of the measured and the use conditions of the sensor: the size of the range; The requirements of the measured position on the volume of the sensor; whether the measurement method is contact or non-contact; the signal extraction method, wired or non-contact measurement; the source of the sensor, whether it is domestic or imported, whether the price can bear, or developed by itself. After considering the above problems, you can determine which type of sensor to choose, and then consider the specific performance indicators of the sensor.
2) Sensitivity selection of ultrasonic ranging sensor
Generally, in the linear range of the sensor, the higher the sensitivity of the sensor, the better. Because only when the sensitivity is high, the value of the output signal corresponding to the measured change is relatively large, which is conducive to signal to process. However, it should be noted that the sensitivity of the sensor is high, and external noise that is not related to the measurement is also easily mixed in, and it will also be amplified by the amplification system, which affects the measurement accuracy. Therefore, it is required that the sensor itself should have a high signal-to-noise ratio to minimize interference signals introduced from the outside. The sensitivity of the sensor is directional. When the measured value is a single vector and the directionality is high, you should select a sensor with low sensitivity in other directions. If the measured value is a multidimensional vector, the smaller the cross-sensitivity of the sensor, the better.
3) Frequency response characteristics of ultrasonic ranging sensors
The frequency response characteristic of the sensor determines the frequency range be measured. It must maintain undistorted measurement conditions within the allowable frequency range. In fact, the response of the sensor always has a certain delay. The shorter the delay time, the better. The frequency response of the sensor is high, and the frequency range of the measurable signal is wide. However, due to the influence of structural characteristics, the inertia of the mechanical system is large. The frequency of the measurable signal of the sensor with low frequency is low. In the dynamic measurement, the response characteristics should be based on the characteristics of the signal (steady-state, transient, random, etc.), so as to avoid excessive fire errors
4) The linear range of ultrasonic ranging sensor
The linear range of the sensor refers to the range in which the output is proportional to the input. In theory, within this range, the sensitivity remains constant. The wider the linear range of the sensor, the larger the range, and it can ensure certain measurement accuracy. When selecting a sensor, when the type of sensor is determined, it is first necessary to see whether its range meets the requirements. But in fact, no sensor can guarantee absolute linearity, and its linearity is also relative. When the required measurement accuracy is relatively low, within a certain range, the sensor with small nonlinear error can be regarded as linear, which will bring great convenience to the measurement.
5) Stability of ultrasonic ranging sensor
After a sensor is used for a period of time, its ability to keep its performance unchanged is called stability. In addition to the structure of the sensor itself, the factors that affect the long-term stability of the sensor are mainly the use environment of the sensor (the use environment is a very important link. To accurately select the ultrasonic ranging sensor, please contact our company staff). Therefore, to make the sensor have good stability, the sensor must have a strong ability to adapt to the environment. Before selecting a sensor, the environment in which it is used should be investigated, and the appropriate sensor should be selected according to the specific use environment, or appropriate measures should be taken to reduce the environmental impact. There are quantitative indicators for the stability of the sensor. After the period of use is exceeded, the calibration should be re-calibrated before use to determine whether the performance of the sensor has changed. In some situations where the sensor can be used for a long time and cannot be easily replaced or calibrated, the stability of the selected sensor is more stringent, and it must be able to withstand the test for a long time.
Transmitting and receiving
Transmitting Sound Pressure Level
Min.110 (30cm/10Vrms Sine Wave) 0dB=0.0002u bar
Min. –75Db/V/μ bar(at 40Khz 0Db=1v/u bar)
Max. Driving Voltage(cont.)
2500±20% at 1KHZ
-20 to +70
-30 to +80
6) Accuracy of ultrasonic ranging sensor
Accuracy is an important performance index of the sensor, it is an important link related to the measurement accuracy of the entire measurement system. The higher the accuracy of the sensor, the more expensive it is. Therefore, as long as the accuracy of the sensor meets the accuracy requirements of the entire measurement system, it does not have to be selected too high. In this way, it is possible to select a cheaper and simpler sensor among many sensors that meet the same measurement purpose. If the measurement purpose is qualitative analysis, use a sensor with high repeat accuracy. It is not appropriate to use a sensor with high absolute value accuracy. If it is for quantitative analysis, accurate measurement values must be obtained, and a sensor with an accuracy level that meets the requirements must be selected.