How does an active or passive temperature compensation of pressure transmitters really work? High-quality pressure transmitters, especially those used in precision critical applications, are nearly always provided with a person temperature compensation. But what’s actually the difference between an active and a passive temperature compensation of these sensors?
Passive temperature compensation: Parts of the characteristic accuracy curve of the pressure sensor are measured at different temperatures during the manufacturing process. Then, the previously determined temperature errors are compensated by passive elements (resistors) within the electronics of the sensor or by corrections of specifically made resistance structures on the sensor element itself (e.g. by laser-trimming). The (passive) resistor elements used have an almost linear temperature behavior, it really is, however, only possible to pay 1st order errors. Temperature errors of higher order, i.e. strong bending of the characteristic curve under temperature, can’t be compensated.
Active temperature compensation: Here too, the characteristic curve of the pressure transmitters is measured at different temperatures during the manufacturing process. However, the pressure transmitter comes with an additional integrated temperature sensor which constantly measures the temperature of the sensor and transfers it to the pressure transmitter?s signal processing. In Lurking , two methods of active temperature compensation are normal: the first method compensates through a limited amount of samples, , i.e. discrete correction values, between which interpolation occurs.
The second method uses the electronics of the transmitter and a higher-order equation resulting from the regression of the acquired measurement values so as to compensate then your expected error. During operation, this signal processing can help you automatically, i.e. ?actively?, compensate the pressure transmitter ?s temperature error utilizing the calculated correction factors inside a specified temperature range (e.g. 10-60�C). The most commonly used method to minimize temperature errors of pressure sensors is a passive temperature compensation. This is the traditional method which is widely used.
However, active temperature compensation is the top quality of possible compensation methods. WIKA has constantly improved and refined this technology recently. The pressure transmitters of WIKA using active temperature compensation therefore include a temperature error which is almost zero within their specified temperature range.