Design And Research Of High-Speed Data Acquisition System Of The Wheel/Rail Simulation Testing Machine Based On Labview

With the rapid development of high-speed railway technology, the challenges facing the railway transportation is unprecedented.The problems on the wear of wheel/rail system have been a major project in many countries. The solution of the problems on high-speed wheel/rail system relies on the experimental apparatus which is fit with the increasing speed. The development and application of data acquisition system with high-efficiency and high-speed on the JD-2wheel-railsimulator has a profound significance.In 21st century, accompanied by the general application of multifunctional, high-performance, low-cost computers and rapid development of large scale integrated circuits and communications technology, the transform of measuring instruments from traditional to digitized and virtual has been an inevitable trend. Using the powerful capacity of date processing and storage of computers, the networking, intellectualization and modularization of the virtual instrument are fully realized. The advantages of multi-tasking, low-cost, high-precision and simple operation are emerged and the instruments are widely used and developed.Based on the idea of virtual instrument and the theory of data acquisition, a five-channel data acquisition system with high-precision, high-speed is designed and developed. And the system basically realized the expected test machine functions. Firstly, some basic theories of data acquisition, which are widely used in data acquisition process, are discussed in this paper, including two sampling methods of digital signals of analog/digital conversion principle and the Nyquist sampling theorem. The design of the entire system includes two components:the development of the hardware system and PC measurement and control program.Advantech company’s PCI-1711L data acquisition card, which makes the largest single-channel sampling rates up to 100KHz, is used in the design of hardware part. In order to achieve continuous isolation signal amplification, ISO124P isolation amplifier is applied, so that the signal is completely isolated from the power. A 2 order Butterworth filter circuit for the disturbance of noise on the signal is also specifically designed in this project. The selection and design of these hardware circuits make the system control the precision and stability of the signal favourably.LabVIEW of the United States NI Company is eventually adopted as the development platform by comparing a variety of programming languages in the development of the software part. Based on the modular design principle, the software system is divided into four modules:data acquisition, data processing, data display and data storage. The greatest innovation of the system development is to solve the difficulties of acquisition, processing, display and storage of large data based on the producer/consumer model of the column as the main program. In addition, multifarious technical means including PCI bus technology, multi-threaded programming technology, etc. is applied in the development of the system which perfectly realized the communication and data transfer between each modules.Finally, the reliability and stability of the system is confirmed effectively by designing a compared experiment and analyzing the obtained experimental data.