基于嵌入式以太网技术的便携式数据采集系统

Implementation of Embedded Ethernet Technology in Portable Data Acquisition System

采用快速以太网传输方案进行现场数据采集具有高速、高抗扰度、传输距离较长、无须编写设备驱动程序等优点。本文介绍了利用嵌入式以太网技术的便携式数据采集系统的设计和实现方法。采用基于飞思卡尔MC9S12NE64微控制器的单芯片嵌入式以太网解决方案简化了电路的硬件设计,提高了系统的可靠性。针对实际应用和硬件特点而采用"自下而上"方法编写的专用IP协议栈与OpenTCP通用协议栈相比,UDP传输速度从15Mbps提高到了24Mbps。该便携式数据采集系统已经在铁道部科研项目"GSM-R频段干扰源快速监测系统研究"中得到了实际应用。

Implementing Fast-Ethernet transmission in spot data acquisition can achieve notable advantages that other serial interfaces don＇ t have, such as high speed, high immunity against interferences, relative long transmission distance and no need for developing device driver. This paper introduces the design and realization of a portable data acquisition system that uses embedded Ethernet technology. The hardware design is based on Freescale MC9S12NE64 MCU, which can provide robust performance with simple circuit structure. An optimized special-purpose IP stack is designed for this application. The software protocol stack is designed using ＂from bottom to top＂ methodology, and it can assemble Ethernet frame and do UDP/IP packaging in a lump. By doing this, the UDP transmission speed is improved to 24Mbps compared with 15Mbps of a common ＂OpenTCP＂ stack. This design has come into use in a research project named ＂Research on A Fast Interference Source Inspection System of GSM-R Band＂.