Research on temperature channel calibration of data-acquisition unit of automatic weather station

A method of utilizing active resistance network to calibrate the temperature channel of data-acquisition unit is proposed in this paper. This method changes gate-source voltage by micro-controller so as to simulate the resistance. Compares resistance value measured by data-acquisition unit with the simulated resistances to calibrate the performance of the data-acquisition unit. Take DT50 data-acquisition unit in CAWS600 AWS for an example. By software commands, output current and A/D sample duration time of the data-acquisition unit temperature channel are changed to resolve the problem of parameters mismatch, then this data-acquisition unit is calibrated effectively. The experiment result shows this approach provide a reliable means to calibrate AWS data-acquisition unit.