基于MSP430的电容式两线制湿度变送器设计  

A Design of Two-Wire Capacitive Humidity Lever Transmitter Based on MSP430

作　　者：潘浩[1] 李力[2] 许炎武[2] 刘鹏希 

机构地区：[1]中国电子科技集团公司第三十八研究所,合肥230088 [2]中国科学技术大学电子科学与技术系,合肥230027

出　　处：《计算机测量与控制》2014年第1期303-305,共3页Computer Measurement &Control

摘　　要：针对工农业生产中远程湿度测量的需求，给出了一种基于湿敏电容的湿度变送器设计方案；电路以低功耗单片机MSP430F2011为核心，通过程序中对片内比较器和GPIO的控制，交替对湿敏电容进行充放电，形成程控振荡器；随后，单片机以晶振为时间基准对振荡频率进行测量并换算成湿度，并通过电流环芯片XTR115输出4－20mA，同时实现环路供电；实验表明，湿度测量误差小于常见湿敏电容本身的误差，能够满足一般需求，并且具有良好的热稳定性，是一种高集成度、高性价比的湿度变送器方案。For remote humidity measurement needs of industrial and agricultural production, this paper presents a humidity sensitive capacitor based transmitter design. Low--power mierocontroller MSP430F2011, the core of the design, charge and discharge the humidity sen- sitive capacitor using the build--in eomparator and GPIO, and make up a program--controlled oscillator. Next, the microeontroller measures the frequency of oscillator based on external crystal, converts to humidity and generates a 4--20mA current loop used XTR115. The experi- ments show that the humidity measurement error is less than the humidity sensitive capacitor error itself, it is possible to meet the general requirements, and has a good thermal stability. It＇s a highly integrated, high cost humidity transmitter design.

关 键 词：湿度变送器 两线制 湿敏电容 电容频率变换 程控振荡器 

分 类 号：TP212.1[自动化与计算机技术—检测技术与自动化装置]