Nowadays, there are many kinds of sensors on the market, and there are many differences in principle and structure. How to select sensors according to specific measurement purposes, measurement objects and measurement environment is the first problem to be solved when performing a certain amount of measurement. When the sensor is determined, the matching measurement method and measuring device can be determined. When we provide solutions, it is very important to choose the right product. As far as the sensor is concerned, there are many types. Once the selection is not good, it will bring a lot of trouble to the later work. An easy way to choose a sensor.

1) Determine the type of sensor based on the measurement object and the measurement environment

To carry out a specific measurement work, we must first consider the principle of the sensor, which needs to be analyzed after analyzing various factors. Because even if it is measuring the same physical quantity, there are many kinds of sensors available for selection. Which kind of sensor is more suitable, you need to consider the following specific problems according to the characteristics to be measured and the conditions of the sensor: the size of the range; The position of the measured position on the sensor volume; the measurement method is contact or non-contact; the signal extraction method, wired or non-contact measurement; the source of the sensor, domestic or imported, the price can withstand, or self-developed.

2) Choice of sensitivity

Generally, in the linear range of the sensor, it is desirable that the sensitivity of the sensor be as high as possible. Because only 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 the external noise that is not related to the measurement is easily mixed in, and is amplified by the amplification system, which affects the measurement accuracy. Therefore, the sensor itself should be required to have a high signal-to-noise ratio, and the plant disturbance signal introduced from the outside is reduced.

3) Frequency response characteristics

The frequency response characteristics of the sensor determine the frequency range to be measured. The measurement conditions must be kept undistorted within the allowable frequency range. In fact, the response of the sensor always has a certain delay, and the shorter the delay time, the better. The frequency response of the sensor is high, and the measurable signal frequency range is wide. Due to the structural characteristics, the inertia of the mechanical system is large, and the frequency of the signal that can be measured by the low frequency sensor is low.

4) Linear range

The linear range of the sensor is 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 the guaranteed measurement accuracy. When selecting a sensor, when the type of sensor is determined, it is first necessary to see if its range meets the requirements. But in reality, any sensor can't guarantee absolute linearity, and its linearity is relative. When the required measurement accuracy is relatively low, within a certain range, the sensor with less nonlinear error can be approximated as linear, which will bring great convenience to the measurement.

5) Stability

The ability of a sensor to remain unchanged after a period of use is called stability. In addition to the structure of the sensor itself, the factors affecting the long-term stability of the sensor are mainly the environment in which the sensor is used. Therefore, in order to make the sensor have good stability, the sensor must have strong environmental adaptability. Before selecting a sensor, investigate the environment in which it is used, select the appropriate sensor according to the specific use environment, or take appropriate measures to reduce the environmental impact.

6) Accuracy

Accuracy is an important performance indicator of the sensor, which is an important part of the measurement accuracy of the entire measurement system. The higher the accuracy of the sensor, the more expensive it is. Therefore, the accuracy of the sensor can be as long as it meets the accuracy requirements of the entire measurement system, and it is not necessary to choose too high. This makes it possible to select a cheaper and simpler sensor among the many sensors that meet the same measurement purpose.