| Today,with the promotion of the fully automated industry,people's attention and requirements for data acquisition systems are increasing day by day.Before equipment and devices are put into use,comprehensive and detailed inspections are required.The reliability,flexibility,and high-speed performance of the testing tools directly affect the final results.There are numerous companies developing data acquisition systems at home and abroad,but the most widely used is the acquisition card of National Instruments in the US.Although it has good performance,it is also relatively expensive.In addition,the company's acquisition card products use a specific modular design,which is less versatile and flexible.Finally,the company has certain restrictions on sales targets and products,and the order cycle and the maintenance period of the product are longer.Based on the above reasons,this thesis decided to independently develop a set of scalable multi-channel data acquisition system.According to practical requirements,the following technical indicators are proposed:8-channel synchronous acquisition function,the highest sampling rate of 200kHz per channel;the system acquisition accuracy reaches 0.1%;the user interface is simple and easy to operate;the system has high reliability,high precision and high speed features.In order to meet the above requirements,the main tasks of this thesis are as follows:(1)Analyze the technical indexs of the system to determine the general scheme of the system.The scheme adopts the combination of FPGA technology and USB2.0 interface technology which consists of hardware and software;(2)The design of system hardware is divided into six parts by function:data acquisition circuit,isolation circuit,transmission control circuit,I/O interface circuit,power supply circuit and hardware reliability.By analyzing the working principle of each module,the module selection and circuit design of the module are completed;(3)The system software adopts the design idea of sub-modules and can be divided into four parts:acquisition card timing control module,USB FX2 firmware module,USB device driver module,and user application module.The design flow and contents of each module is elaborated in detail;(4)The system test is divided into unit testing and overall testing.It mainly tests the data acquisition performance,sampling accuracy,the highest sampling rate,system transmission reliability and transmission rate.Through the analysis of the test results,it is verified that the system achieves the expected technical indexs and meets the actual application requirements. |
