| Universal vibrometer has not the function of lasting and on-line recording. Therefore, it is necessary to develop a more powerful and lower cost vibration recorder for the on-line vibration monitoring of various electronic equipment on vehicle to find out the breakage cause resulting from vibration or impulsion,which is significant in recollecting and analyzing accident, estimating the capability of isolation system and improving the mechanism structure.To resolve the deficiency of universal vibrometer, a framework of the back-end system based on PC with a DAQ board is put forward in this thesis. Firstly, a PC platform composed of the embedded CPU module SPTc-300-VE and CF card is established. On this PC platform, Windows 98plus is transplanted and a DAQ board of PC/104 bus, which can sample 16 channels synchronously and automatically, is extended. A CPLD chip is used to design an ASIC of the DAQ board, which reduces the PCB area and enhances the design quality of hardware.Secondly, to improve the real-time performance of DAQ under the environment of Windows, a device driver in kernel mode is developed using DriverStudio and a DLL which facilitates the upper application call is offered. Continuous DAQ with an interrupted way is accomplished in privilege class of OS. Data loss is avoided effectively in virtue of device file operation and enlarging data buffer zone. A user-mode application based on mutil-thread, which can continuously record vibration in a circular method, is programmed.Thirdly, the whole software structure of recorder is constituted. By modularization and object-oriented programming technology, the on-line monitoring software based on mutil-thread is developed with MeasurementStudio. The watchdog is utilized reasonably, which guarantees the persistence and enhances the reliability of the system.In the end, the application of the recorder in lab is discussed, and some insufficiencies and expectation of the project are pointed out. |
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