基于ADS1248的K型热电偶温度测量系统

摘要

针对某些流量仪表计需要测量流体温度的情况,介绍了一种基于ADS1248模数转换器的K型热电偶高精度温度测量系统.该系统以工业应用所注重的高精度和高可靠性为设计目标,将线性度好、稳定性较高、热电动势较大、测温范围宽、测温精度高的K型热电偶作为温度测量元件,采用ADS1248对K型热电耦的电动势进行采样,再通过微处理器进行信号处理,从而获得流体温度的测量值.同时,采用铂电阻Pt100获取热电偶冷端环境温度,用于补偿热电偶由于冷端温度变化造成的测量误差,从而提高温度测量值的精确度.该系统从硬件设计、软件设计以及器件选择等多个层面考虑了精度问题,实现了一种高精度、高灵活性的热电偶温度采集方法,满足实际应用的要求.%In order to measure the fluid temperature for certain flow meters, a K-type thermocouple high-precision temperature measurement system based on ADS1248 analog-to-digital converter is introduced. The system takes the high precision and high reliability as the design goal,which is emphasized in industrial applications. The K-type thermocouple with good linearity,high stability,high thermoelectric potential, wide temperature measurement range and high temperature measurement precision is selected as the temperature measuring element. The ADS1248 is used for sampling the electromotive force of the K-type thermometer,and then the signal processing is carried out through the microprocessor,thus the measurement value of the temperature of the fluid is obtained. In addition,the temperature of the cold junction temperature of the thermocouple is obtained by the platinum resistance Pt100,which is used to compensate the inaccurate measurement of the thermocouple due to the change of the cold junction temperature,thus the accuracy of the temperature measurement value is improved. For improving the accuracy,various aspects are considered,e. g. ,the hardware design,the software design,the device selection,etc. It realizes a high precision and highly active thermocouple temperature collection method,which meets the requirements of the practical application.