摘要
针对使用中出现的三线制平衡电桥温度测温不准确问题,提出了一种与测量导线电阻无关的恒压分压式三线制热电阻测温方法。在分析了三线制平衡电桥法的基础上,提出了测量电路模型,描述了消除导线电阻的测量方法,分析了提高测量精度的措施,推导出了数字校准公式。使用通用运算放大器OP07与14位分辨率双积分型A/D转换器ICL7135设计了简洁的输入检测电路。经实验验证,该电路对于Pt100热电阻,导线电阻在0～20Ω范围内,热电阻测量误差将优于±0.1%。
In this paper, an accurate method with constant voltage detection for precision measurement of 3-wire thermal resistance is presented. Unlike the 3-wire balance bridge, this method isn＇t affected by lead resistance. The paper designed the measurement circuit model as well as analyzed measunement to improve the measurement precision, and reduced the formula of digital calibration. In addition, a 3-wire thermal resistance input detection circuit was designed by using OP07 and 14-bit A/D ICL7135 converter. The results show that the measurement error is better than ±0.1% for Pt100 thermal resistance with lead resistance is from 0 to 20Ω.
出处
《电子设计工程》
2010年第12期31-33,37,共4页
Electronic Design Engineering
基金
国家自然科学基金资助项目(30271078)
