Design Of High-precision Data Acquisition System Based On 32-bit ADC

High-precision data acquisition technology played a huge role in the fields of factory automation,oil exploration and aerospace.Compared with foreign countries,the data acquisition technology in our country is not mature enough,and the data acquisition products are still in a backward position.It is of great significance to research the high-precision data acquisition system independently for the development of this field in our country.There are many kinds of data acquisition products on the market at present,the bits of the ADC of these products are between 8 bits and 24 bits,the sampling rates are between several hertz and up to one hundred megahertz.In these products,the bits of the ADC of high speed acquisition system are usually less than 24 bits.There is no mature product in the data acquisition system which is higher than 24 bits.Based on the needs of the laboratory research project,this paper designed a kind of data acquisition system based on 32-bit ADC,and this system is aimed at the segment field which has a sampling rate of several hundreds kilohertz and requires high sampling accuracy.The main work of this paper is as follows:1.A low noise simulation circuit was designed.The analog circuit is designed by the high performance amplifier and the number of the devices is minimized to reduce the noise.The AD converter circuit is designed by the 32-bit AD chip of ?-? type.The DC-DC isolated power supply and the digital isolators are used to separate the front analog ground and the back-end digital ground to reduce the crosstalk between the two grounds.In order to improve the synchronization performance of the acquisition board,a FPGA control circuit is designed.2.The data transmission circuit based on USB protocol is designed.In order to meet the requirement of data transmission rate and in consideration of the practicability of the system,a data transmission control circuit based on USB 2.0 bus protocol was designed.The control circuit was designed based on the EZ-USB FX2 chip,and the data transmission mode was the asynchronous Slave FIFO mode.3.Write the PC software based on the virtual instrument development environment lab VIEW.The program of the PC software adopted the buffer design,which solves the unequal rate problem of data generation and data consumption,it is also convenient for the maintenance and upgrade of the program.The PC software has the function of setting acquisition mode,setting acquisition parameters,channel calibration,data display and data storage.4.The system test was carried out in the laboratory environment.The system tests include: short circuit noise test,typical signal test and system channel consistency test.The test results showed that the system meets the design requirements,and it can be applied to high-speed and high-precision data acquisition.