Reference Comparison
The procedure of applying a constant and known pressure to a transducer to determine its output relationship across a specified range defines the standard performance of a pressure sensor. This process is called static pressure calibration and establishes the reference curve used to convert electronic signals into physical units. Deadweight testers are commonly used to generate the reference pressure.
This step is repeated at multiple points to characterize the sensor hysteresis.
Experimental Setup
The transducer is mounted in a manifold connected to the pressure generator and a reference standard. High-stability digital pressure controllers generate the necessary static pressure calibration points with high precision. This setup must be free of leaks to ensure the applied pressure remains constant during the measurement cycle.
Metrological Uncertainty
Sources of error such as local gravity, air density, and piston temperature must be corrected during the calibration process. The uncertainty of the static pressure calibration is calculated by combining these individual error sources. This cumulative uncertainty must be less than one-fourth of the sensor tolerance.
Environmental Influence
Ambient temperature changes can cause zero-shift and sensitivity-shift in the sensor under test. Calibrating the transducer at different temperatures compensates for these environmental variations. This multi-point characterization ensures the sensor remains accurate across its entire specified operating range.
