基于DAC161S997数字电流环变送器的设计

Design of Digital Current Loop Transducer based on DAC161S997

在现代工业检测与控制中,应用模拟的工业电流环变送器来测量压力和温度等参数,并用电位器来校准由温漂和非线性产生的误差,这很难达满足现代工业高精度测量要求。本文针对这一问题,采用超低功耗数字芯片DAC161S997设计数字电流环变送器,应用MCU通过软件校准DAC的增益误差。实验结果表明,数字电流环变送器技术指标满足工业电流环4~20m A要求,数字电流环变送器的误差可以小到0.01%,很好地解决了传统模拟电流环变送器存在的测量准确性和稳定性的问题,数字电流环变送器可在工业领域加以推广应用。

In modern electronics factory detection and control, parameters such as temperature and pressure, may be detected and measured by using industrial analog current loop transducer. The error, resulted from temperature drift and nonlinear characteristic, are then calibrated by using potentiometers. But it cannot meet the requirement of high-precision detection and measurement in modern industrialization. In this study, a novel digital current loop transducer is designed by using super-low power 16-bit digital-to-analog converter DAC 161 $997. Its DAC gain error can be calibrated with the software control method of MCU. The experiments show that its various technical indexes can reach the requirements for industrial current 4-20mA. In addition, its error is highly reduced lower than 0.01%. The accuracy and stability problems are solved in the traditional analog current loop transducer. The digital current loop transducer presented in this study will be employed and extended in a wider industrial application.