基于网络的高精度数据采集卡设计

为了实现数据采集卡高精度和网络传输的要求,提出了一种基于网络的高精度数据采集卡的设计方法.硬件方面,采用ARM为主控CPU,扩展了网络接口芯片,实现了数据采集卡的网络接口功能;采用16位高精度AD转换器AD976,实现了高精确度数据采集的要求;采用FPGA内部逻辑控制AD转换器的时序和模拟开关的切换,并辅以扩展FIFO缓存采样数据的方法实现了8路模拟量的扫描测量,保证了模块的采样率;数字量测量采用光电隔离技术,保证了模块工作的可靠性;软件方面,设计了嵌入式Linux数据采集电路驱动程序和网络通信程序.实现了上位机通过网络接口对模拟量和数字量的采集功能.实际测试表明,数据采集卡采集精确度优于0.05%.

Design of High-precision Data Acquisition Card Based on LAN

In order to achieve the requirements of high-precision and network transmission in data acquisition card,we propose a design of high-precision data acquisition card based on LAN.In terms of hardware,it uses ARM as the host CPU and expands the LAN interface chip.It achieved the features of LAN interface of data acquisition card and high-precision of data acquisition card by high-precision 16-bit AD converter AD976;by using FPGA internal logic to control ADC for sampling and the channels for switching,supplemented by extended FIFO buffer,it achieved the 8-channels scanning measurement of analog signals and ensured the sampling rate of the module;the measurement of digital signals adopts the photoelectric isolation and ensured the reliability of the module.In terms of software,the embedded Linux driver of data acquisition circuit and the network communications application are designed.It achieved the function that a host computer collections analog signals and digital signals through theLAN interface.According to testing,the design of module is reasonable and meets all of the requirements.Acquisition accuracy of the data acquisition card is 0.05%.