Traditionally pressure transducers drift over time and during installation. This has been a continual problem that has requires the end user to offset the reading either at the pressure transducer or the data acquisition system.
The traditional fix has been zero and span potentiometers. However, the offset of the zero has eliminated the original factory calibration by offsetting the curve. This results in inaccurate readings. (See Figure 1)
Why Do They Drift?
Transducers have drifted due to several reasons which include physical damage to the diaphragm and curing of the bonding adhesive between the diaphragm and the strain gauge over periods of time.
CURING OF ADHESIVE
Eliminate the adhesive completely by using sputtered film deposition. (See Figure 2)
The sputtering technique causes the signal per deflection to increase dramatically, meaning the diaphragm flexes less for an equivalent pressure. Therefore we are able to use a thicker diaphragm, which will cause no physical damage.