How does an active or passive temperature compensation of pressure transmitters actually work? High-quality pressure transmitters, especially those found in precision critical applications, are almost always provided with a person temperature compensation. But what is actually the difference between a dynamic 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 designed resistance structures directly 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 compensate 1st order errors. Temperature errors of higher order, i.e. strong bending of the characteristic curve under temperature, can not 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 has an additional integrated temperature sensor which constantly measures the temperature of the sensor and transfers it to the pressure transmitter?s signal processing. Used, two methods of active temperature compensation are common: the first method compensates by means of a limited number of samples, , i.e. discrete correction values, between which interpolation takes place.
The second method uses the electronics of the transmitter and a higher-order equation resulting from the regression of the acquired measurement values so that you can compensate then the 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 really a passive temperature compensation. Approving can be a traditional method which is widely used.
However, active temperature compensation may be the top class of possible compensation methods. WIKA has constantly improved and refined this technology in recent years. The pressure transmitters of WIKA using active temperature compensation therefore include a temperature error that is almost zero within their specified temperature range.