How does a dynamic or passive temperature compensation of pressure transmitters actually work? High-quality pressure transmitters, especially those found in precision critical applications, are nearly always provided with a person temperature compensation. But what’s actually the difference between a dynamic and a passive temperature compensation of the sensors?
Passive temperature compensation: Parts of the characteristic accuracy curve of the pressure sensor are measured at different temperatures through 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 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. In Pummel , two ways of active temperature compensation are normal: the first method compensates by means of a limited amount 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 caused by 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 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. This can be a traditional method that is widely used.
However, active temperature compensation is 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 feature a temperature error that is almost zero in their specified temperature range.