Each pressure sensor has several aspects that will influence how it operates and the applications the pressure sensor operates best for. When choosing a pressure transducer, these six criteria should be taken into account:
Application and measurement type
The standard type of pressure measurement involves: Absolute, gauge, vacuum, differential, bidirectional, and sealed gage. The application restricts the most suitable measurement type.
Seemingly the most critical decision in choosing a pressure sensor is the range of the input signal. For selecting an appropriate pressure transducer based on the measuring pressure range, one must keep in mind two contradictory considerations:
The accuracy of the instrument and its protection from over pressure must be considered. From a precision point of view, the range of a sensor should be sufficiently low, i.e., standard operating pressure near the middle range. So that error, ordinarily a percentage of full scale, is minimized.
On the other hand, one must always admit the consequences of over pressure damage due to defective design, operating errors, or failure to isolate the instrument during pressure-testing and start-up. Therefore, it is essential to designate the required range and the amount of over pressure protection required.
The process fluid is another crucial factor in selecting an appropriate transducer. Often regarded as the “wetted parts”, these materials should be chosen to agree with the fluid being measured. For environments with clean, dry air, just about any material is permitted.
Temperature range and installation environment
Very high temperature or vibration variations restrict what sensors will function correctly. For temperature extremes, thin-film technology is preferred. The extreme temperatures also produce errors in the output of the transducer. This is typically accomplished either by placing them inside purged or explosion-proof houses or intrinsically safe designs. If a compact size is needed, an unamplified transducer is the best choice.
Pressure gauges come in many various accuracies. The accuracy of typical pressure sensors could differ from 0.5% to 0.05 % of the full-scale output. Higher accuracies are wanted when it is essential to read shallow pressures for critical demands.
There are diverse types of outputs for pressure sensors, which was discussed earlier. In general, it is crucial to consider the restrictions and advantages of each output to ascertain the best output type for a specific application.