基于铂电阻的温度高精度测量研究

Study of high-precision temperature measurement based on platinum resistance

针对采用铂电阻对温度进行高精度测量,从硬件电路和曲线拟合2个方面进行了研究。电路上采用同一个电压给传感器恒电流驱动电路和A/D转换电路作参考电压,保证了温度检测的精度,并用最小二乘法直接拟合了描述采样值—温度关系的曲线,弥补了Pt100测温时信号从铂电阻到A/D转换的过程中各个中间环节所产生的偏差。该方法可使测量偏差优于0.05℃,并已在研制的高精度温度温差控制系统中得到应用。

The high-precision t of temperature in platinum resistance is introduced,its research covers two aspects, such as the hardware circuit and curve fitting. In hardware circuits sensor constant current drive circuit and A/D converter circuit use the same voltage as a reference voltage, so it guarantees the temperature measurement accuracy. In curve fitting, it fits the curve which describes the relations of sampling value-temperature by using least squares method, It compensates the deviation which occurs in each middle part of the signal from platinum resistance to the A/D conversion in the temperature measurement of Ptl00. This method can make measurement error superior to 0.05 ℃, and now it applies to the development of high-precision temperature thermal control system.