一种优化的精密温度测量方法

An optimized method of precision temperature measurement

为了精密测量水蒸汽的温度,选择了Pt100测温铂电阻,并根据其非线性特性,提出了一种恒流源加电压-频率(V-F)转化器电路的优化测量方法。首先,采用1 mA的恒流源,保证流过铂电阻的电流恒定而且足够小,使电阻两端的电压差与电阻值成线性输出关系;其次,采用差分三运放放大电路,将电压信号按比例放大;然后,采用精密的电压-频率转化器,将频率送给微处理器;最后,通过微处理器的采集频率以及简单的软件补偿,得到精密的温度值。试验结果表明,该方法能精密、方便、简单地采集与校准温度。

In order to measure the temperature accurately, the PtlO0 platinum resistance was choosen, and according its nonlinear properties, an optimized measurement method that using constant current source and voltage-to-frequency converters was developed. Firsly, the I mA constant current source was used, in order to ensure the flow of current platinum resistance constant and small enough. Secondly, three op amp differential amplifier circuit was used to enlarge the voltage signal proportionally. Then, the precision voltage-to-frequency converter was used to send the frequency to microprocessor. Finally, by means of the collection frequency of microprocessor and simple software compensation, precision temperature was obtained. The test results show that this method can collect and calibrate the temperature accurately, conveniently and simply.