基于线性化技术的渗透压摩尔浓度测量系统

在冰点下降原理基础上,研究了渗透压摩尔浓度测量系统测量过程和参数设置问题。应用100μA恒流源供电方式法和二阶范数最小二乘法曲线拟合算法相结合,提出了NTC热敏电阻器线性化新方法,建立了NTC热敏电阻器的Matlab修正模型,实现了NTC热敏电阻器线性化处理。在此基础上,采用高分辨率A/D进行模拟信号转换,完成了渗透压摩尔浓度测量系统的设计。经实验验证,测量精度为±1 mmol/kg(≤500 mmol/kg)或RSD≤±0.2%(>500 mmol/kg)。

Osmotic pressure molar ratio measuring system based on technology of linearization

On the basis of theory of cryoscopy,the measuring process and the parameter selection of osmotic pressure molar ratio measuring system have been studied.A new method of negative temperature coefficient(NTC) thermistor linearization is brought up by using 100 μA constant current source power supply combined with 2 order norm least squares curve fitting algorithm,and also a Matlab correctional model of NTC thermistor is built up by which the NTC thermistor linearization problem is solved.On that basis,analog signal transform is carried out and with high resolution AD converter design of the osmotic pressure molar ratio measuring system is accomplished. According to the experimental verification,the osmometer is able to measure osmotic pressure molar ratio with a precision of ± 1 mmol / kg(≤500 mmol / kg) or RSD ≤ ± 0.2 %(> 500 mmol / kg).