The Design And Implementation Of Multi-channel Data Acquisition System

The technology of data acquisition is widely used in communication, radar, aerospace, industry and so on. With the rapid development of microelectronics and computer technology, the performance of data acquisition system is constantly improved, and the function is constantly enhanced.At the same time the technology has been very widely used on the field of railway fault diagnosis test.In the railway fault diagnosis and detection system researchers acquire some related signals synchronously when the key signal is obtained in order to get better analysis of the modern signal processing system. The previous multi-channel time-division multiplexing data acquisition system can only implement the cyclical multi-channel signal acquisition, but not implement the multi-channel signal acquisition at the same time. Furthermore, the high data acquisition rate can not be achieved in this system. The multi-channel synchronous data acquisition system can just makes up the deficiencies of the time-division multiplexing data acquisition system. In order to solve the above several kinds of problems,A PCI-104 multi-channel parallel data acquisition system based on FPGA is designed.This paper discusses the multichannel parallel data acquisition system AI308₃ the designing method and its technology research.AI308V₃ multichannel parallel data acquisition system were introduced in this paper and also introduced the designing method and its technology research,Including the design of the hardware circuit, the board performance testing and function debugging and the development of the acquisition and processing software.The paper comes from the monitoring project of the railway vibration monitoring in a very bad environment.Thesis results can make the level of the rail vibration monitoring and fault diagnosis in China further ascension,At the same time improve the degree of its convenience.The paper made the following several aspects of progress.AI308V₃ working environment requirement for-40℃-85℃ long-term stability and can work under the vibration environment.Request AI308V₃ system has larger changes in ambient temperature environment normal work performance and seismic performance,And the characteristics of the portable.In view of the data acquisition part of the front end of the railway fault diagnosis and monitoring system,It uses PCI-104 shape,All components of the 8 channel data acquisition channel are integrated on the board of the X 90mm 96mm,Complete portable system requirements.On the basis of a comparison between the performances of the various components, Select components that can work stably in the environment of large temperature difference changes.In the design of the card at the same time all adopt the patch design reduces the footprint of the board, And to upgrade the board thickness to 2 mm makes the card can be better with shock and increase mechanical properties.The pci-104 for practical applications, can have more design space in Limited board, more additional features, connectors, and other unique technology added to the whole system, in order to optimize and upgrade the whole system.In addition, the front-end circuit of the data acquisition system is improved according to the different sensor output signal types,At the same time according to the system requirements, based on the analysis of data collected by the sensor on the design of the filter, follow, amplification and signal conditioning circuit integrated directly into the signal conditioning circuit to each data acquisition channel, so that the system can be directly facing the sensor without additional signal conditioning, making the system more suitable for industrial data acquisition applications.Use LTC1864 16 bit A/D converter is designed A/D converter circuit, not only simplifies the design of the workload, but also improve the performance of the system.Based on the research of hardware and technology, a multi-channel parallel data acquisition and processing software AI308V₃ is developed, which is based on the LabWindows/CVI platform, The experiment of multi-channel data acquisition is carried out in the high temperature test box, Continuous collection of signals during temperature rise to 85 degrees, The waveforms collected and the waveforms collected at room temperature were compared and analyzed. Results showed that the multi-channel parallel data acquisition system in the environment of the large temperature difference can realize stable data collection. In the vibration device using ICP data collected vibration acceleration sensor,And collect these data processing and analysis, show that AI308V₃ has good shockproof performance, and has the very high mechanical stability.In the end, the function of each part of the system has been tested and debugged, And sums up the problems appeared in the process of test, Give all the solutions to these problems, After the completion of the test, Debug the system and write the testing report.Thesis research and the experimental results show that, The data acquisition system is stable and reliable, It can be stably worked at the temperature of-40℃～85℃. The sampling rate reached 80Ksps,The sample rate can be set to 80K,40K,20K,10K,5K,This data acquisition system is stable, reliable, fast data processing, achieved the expected design requirements, very suitable for the industrial field data collection.