5 Specifications to Consider in Pressure Sensor Selection
During the selection of the pressure sensor, the right specifications are the important thing that must be considered carefully. Different types of pressure sensors vary widely in principle and structure. How to properly select the sensor according to the specific measurement purpose, measurement object and measurement environment is the first problem to be solved before pressure measurement. After the selection of the pressure sensor have determined, the matching measurement method and measurement device can be determined. The success or failure of the measurement result largely depends on whether the sensor selection is reasonable.
To carry out a specific measurement, the first thing to consider is the pressure sensor that based on which principle. This requires analysis of various factors before decision. Because even the measured medium is the same medium, there are many kinds of sensors available. Which kind of pressure sensor is more suitable, you need to consider the following specific problems according to the characteristics of the measured medium and the conditions of the sensor use. The measuring range, the measurement site requirements for the sensor volume; the measurement method is contact or non-contact; the signal output mode; the source of the sensor, the price, etc. For example, diffused silicon pressure sensor is a common pressure sensor in industrial automation control. It has large signal output, high resolution, high sensitivity, small size and easy installation. It provides a great advantage for the transmission conditioning line in back-end. In addition, the diffused silicon pressure sensor can be compensated twice, that is, the sensitivity temperature coefficient and the zero temperature coefficient of the sensor can be compensated, even if the finished core can be compensated twice.
After considering the above questions, you can determine which type of pressure sensor to use, and then consider the specific specification and performance of the sensor.
1. The pressure sensor sensitivity
In the linear range of the sensor, it is often 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 change of measured medium will be relatively large, which is beneficial to signal processing. However, it should be noted that the sensitivity of the sensor is high, and external interference substances that are not related to the measurement are easily mixed in and amplified by the amplification system, which affects the measurement accuracy.
The sensitivity of the pressure sensor is directional. When the measured pressure is a single vector and its directional requirements is high, the sensor with low sensitivity to other directions should be selected. If the measured pressure is a multidimensional vector, the cross sensitivity of the sensor is required to be as small as possible.
2. The pressure sensor frequency response
The frequency response characteristics of the pressure sensor determine the frequency range of the measured pressure. Undistorted measurement conditions must maintained within the allowed frequency range. In fact, the response of the sensor will always have a certain delay, so we can only demand the delay time as short as possible.
The frequency response of the pressure sensor is high and the frequency range of the measurable signal is wide. Due to the influence of structural characteristics and the large inertia of the mechanical system, sensors with low frequency response have lower measurable signal frequency.
3. The pressure sensor 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 its measuring range and guarantee a certain measurement accuracy. When selecting a pressure sensor, after the type of sensor have determined, it is first necessary to see if its range meets the requirements.
However in fact, any pressure 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 approximated as linear, which will bring great convenience to the measurement.
4. The pressure sensor stability
The ability of a pressure sensor to remain unchanged after using a certain time is called stability. Factors affecting the long-term stability of the sensor are mainly the environment in which the sensor is used, in addition to the structure of the sensor itself. Therefore, in order to make the pressure sensor have good stability, the sensor must have strong environmental adaptability.
Before selecting a pressure sensor, investigate the environment in which it is used, and select the appropriate pressure sensor according to the specific use environment, or take appropriate measures to reduce the environmental impact.
Stability of the pressure sensor has a quantitative indicator. After the usage period, it should be recalibrated before use to determine whether the performance of the sensor have changed.
In some applications where the pressure sensor is required for long-term use and cannot be easily replaced or calibrated, the selected sensor has stricter stability requirements and is capable of withstanding long-term tests.
5. The pressure sensor accuracy
Accuracy is an important performance specification of a pressure sensor and 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 satisfies the accuracy requirements of the entire measurement system, and it is not necessary to demand excessive accuracy. It makes it possible to select a relatively inexpensive and simple one among a plurality of pressure sensors that satisfy the same measurement purpose.
If the purpose of the measurement is qualitative analysis, a pressure sensor with high repeatability is enough. It is not advisable to use a sensor with high absolute value accuracy. If it is for quantitative analysis, accurate measurements must be obtained. At this time, it is necessary to select a pressure sensor whose accuracy level can meet the requirements.
To carry out a specific measurement, the first thing to consider is the pressure sensor that based on which principle. This requires analysis of various factors before decision. Because even the measured medium is the same medium, there are many kinds of sensors available. Which kind of pressure sensor is more suitable, you need to consider the following specific problems according to the characteristics of the measured medium and the conditions of the sensor use. The measuring range, the measurement site requirements for the sensor volume; the measurement method is contact or non-contact; the signal output mode; the source of the sensor, the price, etc. For example, diffused silicon pressure sensor is a common pressure sensor in industrial automation control. It has large signal output, high resolution, high sensitivity, small size and easy installation. It provides a great advantage for the transmission conditioning line in back-end. In addition, the diffused silicon pressure sensor can be compensated twice, that is, the sensitivity temperature coefficient and the zero temperature coefficient of the sensor can be compensated, even if the finished core can be compensated twice.
After considering the above questions, you can determine which type of pressure sensor to use, and then consider the specific specification and performance of the sensor.
1. The pressure sensor sensitivity
In the linear range of the sensor, it is often 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 change of measured medium will be relatively large, which is beneficial to signal processing. However, it should be noted that the sensitivity of the sensor is high, and external interference substances that are not related to the measurement are easily mixed in and amplified by the amplification system, which affects the measurement accuracy.
The sensitivity of the pressure sensor is directional. When the measured pressure is a single vector and its directional requirements is high, the sensor with low sensitivity to other directions should be selected. If the measured pressure is a multidimensional vector, the cross sensitivity of the sensor is required to be as small as possible.
2. The pressure sensor frequency response
The frequency response characteristics of the pressure sensor determine the frequency range of the measured pressure. Undistorted measurement conditions must maintained within the allowed frequency range. In fact, the response of the sensor will always have a certain delay, so we can only demand the delay time as short as possible.
The frequency response of the pressure sensor is high and the frequency range of the measurable signal is wide. Due to the influence of structural characteristics and the large inertia of the mechanical system, sensors with low frequency response have lower measurable signal frequency.
3. The pressure sensor 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 its measuring range and guarantee a certain measurement accuracy. When selecting a pressure sensor, after the type of sensor have determined, it is first necessary to see if its range meets the requirements.
However in fact, any pressure 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 approximated as linear, which will bring great convenience to the measurement.
4. The pressure sensor stability
The ability of a pressure sensor to remain unchanged after using a certain time is called stability. Factors affecting the long-term stability of the sensor are mainly the environment in which the sensor is used, in addition to the structure of the sensor itself. Therefore, in order to make the pressure sensor have good stability, the sensor must have strong environmental adaptability.
Before selecting a pressure sensor, investigate the environment in which it is used, and select the appropriate pressure sensor according to the specific use environment, or take appropriate measures to reduce the environmental impact.
Stability of the pressure sensor has a quantitative indicator. After the usage period, it should be recalibrated before use to determine whether the performance of the sensor have changed.
In some applications where the pressure sensor is required for long-term use and cannot be easily replaced or calibrated, the selected sensor has stricter stability requirements and is capable of withstanding long-term tests.
5. The pressure sensor accuracy
Accuracy is an important performance specification of a pressure sensor and 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 satisfies the accuracy requirements of the entire measurement system, and it is not necessary to demand excessive accuracy. It makes it possible to select a relatively inexpensive and simple one among a plurality of pressure sensors that satisfy the same measurement purpose.
If the purpose of the measurement is qualitative analysis, a pressure sensor with high repeatability is enough. It is not advisable to use a sensor with high absolute value accuracy. If it is for quantitative analysis, accurate measurements must be obtained. At this time, it is necessary to select a pressure sensor whose accuracy level can meet the requirements.