During static pressure measurement, i.e. when a static load is applied, piezoelectric pressure sensors with charge output (PE) display a small drift due to their principle of operation. By contrast, sensors based on the piezoresistive principle largely operate free of drift.
Measuring small and large static pressures over a long period
In piezoelectric pressure sensors with charge output (PE), the drift value always remains the same when a static load is applied, regardless of the measured pressure. Thus, the relative measurement error caused by the drift is particularly unfavorable when small pressures are to be measured over a long period.
However, measuring large static pressures over lengthy measuring periods don’t pose any problem. With piezoelectric pressure sensors, therefore, the measuring time depends on the requirements for accuracy and the kind of pressure to be measured.
The graphic in fig. 2 displays whether a piezoelectric pressure sensor can be used for measuring a static pressure or whether it is appropriate to use a piezoresistive pressure sensor only. The graphic clearly outlines that long measurement times don’t pose any problems for piezoelectric pressure sensors if the pressures are large enough. But piezoresistive pressure sensors are clearly preferable for long-term monitoring tasks.