Development of an automatic calibration device for high-accuracy low temperature thermometers

Based on the analysis and investigation of calibration systems for high-accuracy low temperature thermometers, a new facility for automatic calibration of high-accuracy low temperature thermometers was developed. Continuous calibration for multiple points can be made automatically with this device. According to the thermophysical characteristics of the constant-temperature block in this device, segmented Fuzzy-PID (proportional-integral-differential) algorithm was applied. The experimental results showed that the temperature fluctuation was smaller than ±0.005 K in 30 min. Therefore, this new device can fully meet the calibration requirement of high-precision low temperature thermometers.