Select High Performance Pressure Sensor by Judging Stability
The pressure sensor stability is a performance that make the sensor to remain unchanged after using a certain time. When selecting a pressure senor, the stability is an important specification affecting future use. This article lists four methods to help users easily judge the pressure sensor stability. These methods are simple and practical and avoid the selection of pressure sensors with poor stability.
1. Observe the natural jump variable of the pressure sensor output signal when energized
For a pressure sensor with good stability, its zero-point output jump variable should be <0.01% FS in five consecutive minutes. For a pressure sensor with poor stability, its zero-point output jump variable should be >0.06% FS in five consecutive minutes. For a typical pressure sensor with 4-20 mA output, 0.01% FS is equal to 0.0016 mA and 0.06% FS is equal to 0.0096 mA.
2. Sense the amount of change in the output signal
When the power is on, touch the outer casing of the pressure sensor by hand to sense the amount of change in the output signal. The variation is >0.1% FS, which is a typical sign of poor anti-electromagnetic interference performance. For a typical pressure sensor with 4-20 mA output, 0.1% FS is equal to 0.016 mA.
3. Observe the change in pressure sensor zero output for one hour in a row
For the pressure sensor with good stability, the change amount should less than one-half of the maximum allowable error specified by the accuracy level of pressure sensors.
For the pressure sensor with poor stability, the change amount should more than one-half of the maximum allowable error specified by the accuracy level of pressure sensors. If the user encounters such a pressure sensor, we can reduce its accuracy level by 10 times.
4. When the pressure sensors using small signal removal technology
Small signal removal means that when the true output value of the pressure sensor is less than a threshold close to the zero output such as 1% FS, the sensor will force the output signal to zero, that is, force the display value to be equal to zero. If users encounter a pressure sensor whose display value is always 0.000 or 0.0000 and the last value does not change, you need to pay special attention. Testing a pressure sensor using a small-signal ablation technique requires the use of a standard pressure gauge with an accuracy greater than 3 times the accuracy of the sensor. First, pressurize to about 10% FA. After the last value of the pressure gauge display value has changed, keep the constant pressure, and then test with the steps 1, 2 and 3 described above.
In general, the pressure sensor must have high anti-interference performance first, then its high stability can be achieved. With the basic premise of high stability, it is possible to manufacture pressure sensors with additional capabilities such as high accuracy and high reliability. Therefore, in general, high accuracy and high reliability are in the same line. Do not blindly believe in the high reliability in low accuracy instruments.
Through the above electrical performance test, the stability and anti-interference ability of the pressure sensor can be basically judged. However, how much water can be packed in the barrel depends on the shortest piece of wood, so it has to be evaluated from the structural materials and packaging process. For example, whether the machining is fine, whether the materials used are genuine, etc.
1. Observe the natural jump variable of the pressure sensor output signal when energized
For a pressure sensor with good stability, its zero-point output jump variable should be <0.01% FS in five consecutive minutes. For a pressure sensor with poor stability, its zero-point output jump variable should be >0.06% FS in five consecutive minutes. For a typical pressure sensor with 4-20 mA output, 0.01% FS is equal to 0.0016 mA and 0.06% FS is equal to 0.0096 mA.
2. Sense the amount of change in the output signal
When the power is on, touch the outer casing of the pressure sensor by hand to sense the amount of change in the output signal. The variation is >0.1% FS, which is a typical sign of poor anti-electromagnetic interference performance. For a typical pressure sensor with 4-20 mA output, 0.1% FS is equal to 0.016 mA.
3. Observe the change in pressure sensor zero output for one hour in a row
For the pressure sensor with good stability, the change amount should less than one-half of the maximum allowable error specified by the accuracy level of pressure sensors.
For the pressure sensor with poor stability, the change amount should more than one-half of the maximum allowable error specified by the accuracy level of pressure sensors. If the user encounters such a pressure sensor, we can reduce its accuracy level by 10 times.
4. When the pressure sensors using small signal removal technology
Small signal removal means that when the true output value of the pressure sensor is less than a threshold close to the zero output such as 1% FS, the sensor will force the output signal to zero, that is, force the display value to be equal to zero. If users encounter a pressure sensor whose display value is always 0.000 or 0.0000 and the last value does not change, you need to pay special attention. Testing a pressure sensor using a small-signal ablation technique requires the use of a standard pressure gauge with an accuracy greater than 3 times the accuracy of the sensor. First, pressurize to about 10% FA. After the last value of the pressure gauge display value has changed, keep the constant pressure, and then test with the steps 1, 2 and 3 described above.
In general, the pressure sensor must have high anti-interference performance first, then its high stability can be achieved. With the basic premise of high stability, it is possible to manufacture pressure sensors with additional capabilities such as high accuracy and high reliability. Therefore, in general, high accuracy and high reliability are in the same line. Do not blindly believe in the high reliability in low accuracy instruments.
Through the above electrical performance test, the stability and anti-interference ability of the pressure sensor can be basically judged. However, how much water can be packed in the barrel depends on the shortest piece of wood, so it has to be evaluated from the structural materials and packaging process. For example, whether the machining is fine, whether the materials used are genuine, etc.