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%.