基于磁通门电流传感器、精密电阻、20bit SAR型A/D转换器和树莓派设计了量程范围为10~1000A的高精度交直流电流表。通过硬实时Linux内核和迭代Hampel滤波器等技术规避了树莓派在硬件实时性上的缺点,充分发挥其在运算能力和可拓展性方面的优势,实现了在误差范围不超过±0.02%的前提下,具有测试数据存储、导出、远程连接、程序迭代便捷等特点。此外,从设计原理上对整套测量系统进行理论误差估计,证明了其能够达到0.02%的测量精度。
Abstract
A high-precision DC&AC digital ammeter with range 10A to 100A is introduced, which is based on fluxgate current sensor, precise resistor, 20-bit A/D converter and Raspberry Pi. Hard real time kernel and Hample Filter is applied to avoid the shortcomings of the Raspberry Pi in real-time hardware, highlighted with powerful calculate ability and flexibility. The ammeter achieved precise measurement with the relative error below ±0.02%, and is given the ability of storing measurement result, remote connection, rapidly software upgrading. The error level in theory is investigated in terms of circuit design and software design, keeping consistency with the experimental result.
关键词
计量学 /
宽量程 /
交直流电流表 /
树莓派
Key words
metrology /
wide-Range /
DC& /
AC digital ammeter /
raspberry Pi
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