Modern sensors vary widely in principle and structure. How to choose sensors reasonably according to the specific measurement purpose, measurement object and measurement environment is the first problem to be solved when measuring a certain quantity. When the sensor is determined, the matching measuring method and measuring equipment can also be determined. The success or failure of measurement results depends to a great extent on whether the selection of sensors is reasonable.

1. Determine the type of sensor according to the measurement object and measurement environment.

To carry out a specific measurement, we should first consider what kind of sensor is used, which needs to be determined after analyzing many factors. Because, even when measuring the same physical quantity, there are many kinds of sensors to choose from, and which one is more suitable, we need to consider the following specific problems according to the measured characteristics and the use conditions of the sensor: the size of the measuring range; Requirements of the measured position on the sensor volume; Whether the measurement method is contact or non-contact; Signal extraction method, wired or non-contact measurement; The source of the sensor, domestic or imported, affordable, or self-developed.

After considering the above problems, we can determine which type of sensor to choose, and then consider the specific performance index of the sensor.

2, the choice of sensitivity

Generally, within 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 beneficial to signal processing. However, it should be noted that the sensitivity of the sensor is high, and external noise unrelated to the measurement is easy to be mixed in, and it will also be amplified by the amplification system, which will affect the measurement accuracy. Therefore, it is required that the sensor itself should have a high signal-to-noise ratio and try its best to reduce the interference signals introduced from the outside.

The sensitivity of the sensor is directional. When the measured quantity is unidirectional, and its directivity is required to be high, sensors with low sensitivity in other directions should be selected; If the measured vector is a multidimensional vector, the smaller the cross sensitivity of the sensor is, the better.