How to choose a practical pressure sensor (2)
3. What is the temperature resistance of the sensor?
A: Pressure sensors, like all physical equipment systems, can cause errors or even be unusable in extreme temperature environments. Generally each sensor will have two temperature ranges, the working range and the compensation range. The compensation range is included in the scope of work.
The working range means that within this range, the sensor can be exposed to the medium without damage after it is energized. However, this does not mean that the performance can reach the nominal specification (temperature coefficient) when it is outside the compensation range.
The compensation range is generally a narrower range within the working range. Within this range, the sensor ensures that the nominal specifications are met. The change in temperature affects the sensor in two ways, one causing zero drift and the other affecting the output of the entire range. The sensor specification should list these errors in the following form: ±x% full scale / °C, ±x% reading / °C, ±x% full scale over temperature compensation range, or ±x% over temperature compensation range reading. Failure to do so will cause uncertainty in your use. So is the change in sensor output due to pressure changes or temperature changes? Temperature effects will be the most complex part of understanding how to use the sensor.
4. What output is selected?
A: A typical sensor has a millivolt output, or a voltage amplification, or milliamp, or frequency output. The type of output selected depends on the distance between the selected sensor and the system control or display component, noise, and other electrical disturbances, as well as whether amplification is required, where the amplifier is best placed. For many original equipment manufacturers, their control elements and sensors are very short, so millivolt output is generally sufficient and less expensive.
If sensor output amplification is required, it is easier to use another sensor with a built-in amplifier. In long-distance cables, or in areas with large electrical noise, mA output or frequency output is required. In environments with strong RF interference and electromagnetic interference, it is also necessary to consider adding additional shielding or filtering equipment outside the milliamp and frequency output.
