中文摘要：

提出了一种可对直流电流进行精密测量的设计方案。系统采用STM32型单片机作为微处理控制,控制高精度的模数转换器对通入待测电流的采样电阻上的电压进行采样,并进行后续的数据处理、前端触摸屏显示及与计算机进行通信。针对采样电阻通电后因发热导致阻值变化从而引起电流测量不准确的问题,采用中国计量科学研究院研制的＂极低负载效应分布式采样电阻＂对被测电流进行采样,保证了电流采样及测量的准确度。测量仪参数设置可通过触摸屏进行也可以由计算机端的测控软件通过串口对其进行设置,并实现数据的采集和存储。对-1 A-1 A范围的直流电流进行了测试以考察文中提出的设计方案,通过更换不同阻值的采样电阻,可进一步扩展电流测量范围。文中还设计出测试方案对其中核心的数字采样模块以及整体系统进行了测试。该设计方案具有测量准确度高,稳定性好,易操作等优点,能满足实际应用的需求。

英文摘要：

This paper proposes a design scheme of precision measurement for direct current. The system adopts STM32 type single-chip computer as the microprocessor control,the AD converter for access control and high precision to measure voltage sampling on current sampling resistor,which conducts the subsequent data processing,the front touch screen display and communicate with the computer. For inaccurate current measurement problem which is caused by the changing of electrify resistance in sampling resistance after heat,this paper adopts ＂very low load effect distributed sampling resistor＂for the current samples to be measured which is developed by the National Institute of Metrology to ensure the accuracy of current sampling and its measurement. Measuring parameter is set by the touch screen and can also be set by measurement and control software of computer through the serial port,and realizes data acquisition and storage. This paper conducts a-1 A ~ 1 A range of dc current measurement to test the design scheme,and the current measuring range can be further expanded by changing the different resistance of sampling resistors.This paper also designs test scheme for high precision analog-to-digital conversion of these core modules and the whole system was tested,and the measurement scheme has the advantages of high measurement accuracy,good stability,and easy operation,which can meet the needs of practical application.