In terms of industrial sensor selection – Turck

1. According to the measurement target and measurement environment

In order to carry out a detailed measurement work, it is necessary to first consider the principle of the sensor to choose, which needs to be analyzed and many elements can be confirmed. Because, even if the same physical quantity is measured, there are a variety of principles of sensors to choose from, which principle of the sensor is more suitable, it is necessary to consider the following detailed issues according to the characteristics of the measurement and the use conditions of the sensor: the size of the range, the requirements of the measured position on the volume of the sensor, the measurement method of contact or wrong contact, the method of signal extraction, wired or wrong contact measurement, the origin of the sensor, whether the domestic is still imported, whether the price is acceptable, or self-developed; After considering the above questions, it is possible to determine the type of sensor to use, and then consider the detailed functional indicators of the sensor.

In terms of industrial sensor selection – Turck

In terms of industrial sensor selection – Turck

2. Selection of sensitivity

In general, within the linear scale 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 processing. However, it should be noted that the sensitivity of the sensor is high, and the external noise that has nothing to do with the measurement is also simply mixed, and it will also be amplified by the amplification system, which will affect the measurement accuracy. Therefore, the sensor itself should have a high signal-to-noise ratio to minimize the interference signal introduced from the outside world.

The sensitivity of the sensor is directional. When the measured quantity is a one-vector quantity and has high requirements for its directionality, the sensor with low sensitivity in other directions should be selected. If the measured is a multi-dimensional vector, the smaller the cross-sensitivity of the sensor, the better.

3. Frequency response characteristics

The frequency response characteristics of the sensor determine the frequency scale to be measured, and it must be maintained without distortion within the allowable frequency scale. In fact, there is always a definite delay in the sensor's response, and hopefully the shorter the delay, the better. The higher the frequency response of the sensor, the wider the frequency scale of the signal that can be measured. In dynamic measurement, the response characteristics of the signal (steady-state, transient, random, etc.) should be used to avoid excessive errors.

4. Linear scale

The linear scale of a sensor refers to the size at which the output is proportional to the input. Theoretically, the sensitivity sticks to a fixed value at this scale. The wider the linear scale of the sensor, the greater its measuring range and the guaranteed measurement accuracy. When selecting a sensor, when confirming the type of sensor, the first thing to do in the future is to see whether the range meets the requirements.

But in reality, no sensor can guarantee absolute linearity, and its linearity is also relative. When the required measurement accuracy is relatively low, within a certain scale, the sensor with small nonlinear error can be approximately regarded as linear, which will bring great convenience to the measurement.

5. Stability

The ability of a sensor to persist in its function after a period of use is known as 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. Therefore, in order for the sensor to have outstanding stability, the sensor must have strong environmental adaptability.

Before selecting a sensor, it is necessary to investigate the environment in which it will be used, and select the appropriate sensor based on the detailed use environment, or take appropriate measures to reduce the impact of the environment.

There are quantitative indicators for the stability of the sensor, and after the service life has passed, it should be recalibrated before use to confirm whether the function of the sensor has changed.

In some occasions where the sensor is required to be used for a long time and cannot be easily replaced or calibrated, the stability requirements of the selected sensor are more stringent, and it is necessary to be able to withstand long-term detection.

6. Accuracy

Accuracy is an important functional index of the sensor, and 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 its price, therefore, the accuracy of the sensor only needs to meet the accuracy requirements of the entire measurement system, and does not have to be too high. In this way, it is possible to choose the cheaper and simpler sensor Atlas air compressor accessories among many sensors that meet the same measurement purpose.

If the purpose of measurement is qualitative analysis, it is sufficient to choose a sensor with high repeatability, and it is not appropriate to choose a sensor with high absolute accuracy; If it is necessary to obtain accurate measurement values for quantitative analysis, it is necessary to select a sensor with an accuracy level that satisfies the requirements.

For some special use occasions, if you can't choose a suitable sensor, you need to design and manufacture the sensor yourself. The function of the self-made sensor should be satisfactory to the use requirements.

In terms of industrial sensor selection – Turck

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