【概要描述】Linear range: 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 is, the larger its range is, and can ensure a certain measurement accuracy. When selecting the sensor, when the type of sensor is determined, the first thing to see is whether its range meets the requirements. However, in fact, any sensor can not guarantee the 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. Stability: The ability of the sensor to keep its performance unchanged after a period of use is called stability. The factors that affect the long-term stability of the sensor are not only the layout of the sensor itself, but also the use environment of the sensor. Therefore, to make the sensor have good stability, the sensor must have strong adaptability to the environment. Before selecting the sensor, its use environment should be investigated, Select appropriate sensors according to the specific use environment, or take appropriate measures to reduce the impact of the environment. The stability of the ultrasonic sensor has quantitative indicators. After the service life, it should be re-calibrated before use to determine whether the performance of the sensor has changed. In some places where the sensor is required to be used for a long time, but cannot be easily replaced or calibrated, the stability of the selected sensor is more strict and can withstand the test for a long time. Frequency response characteristics: the frequency response characteristics of the ultrasonic sensor determine the frequency range to be measured, and must remain undistorted within the allowable frequency range. In fact, the response of the sensor always has a fixed delay. It is hoped that the shorter the delay time is, the better the frequency response of the sensor is, the wider the measurable signal frequency range is. In dynamic measurement, the response characteristics of the signal, such as steady state, transient, random, etc, Avoid excessive errors. Accuracy: It is an important performance index of the sensor, and it is an important link related to the measurement accuracy of the whole measurement system. The higher the accuracy of the ultrasonic sensor, the more expensive its cost is. Therefore, the accuracy of the sensor can meet the accuracy requirements of the whole measurement system as long as it does not have to be too high, so that the relatively cheap and simple sensor accessories can be selected from many sensors that meet the same measurement purpose. If the measurement purpose is qualitative analysis, the sensor with high repetition accuracy can be selected, and the sensor with high measurement accuracy should not be selected; If it is necessary to obtain the measured value for quantitative analysis, it is necessary to select the sensor whose accuracy grade can meet the requirements. For some special places where it is impossible to select the appropriate sensor, it is necessary to design and manufacture the sensor by itself. The performance of the self-made sensor should meet the use requirements.