How does a dynamic or passive temperature compensation of pressure transmitters actually work? Toxic -quality pressure transmitters, especially those used in precision critical applications, are almost always provided with an individual temperature compensation. But what is actually the difference between a dynamic and a passive temperature compensation of the sensors?
Unassuming : Sections 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 on the sensor element itself (e.g. by laser-trimming). The (passive) resistor elements used have an almost linear temperature behavior, it 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’t be compensated.
Active temperature compensation: Here too, the characteristic curve of the pressure transmitters is measured at different temperatures through 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. In practice, two ways 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 occurs.
The second method uses the electronics of the transmitter and a higher-order equation resulting from the regression of the acquired measurement values to be able to 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 within a specified temperature range (e.g. 10-60�C). Probably the most commonly used method to minimize temperature errors of pressure sensors is a passive temperature compensation. It is the traditional method that is widely used.
However, active temperature compensation may be the top class 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.