| This article describes the development of the computer-aided monitoring system of the fatigue tester: the background of study, the relevant theory, the constitution of the system, the operation principle of the monitoring system,.the process of development, and the operations process of the system. The tester will be monitored by this system.First of all, the article summarizes the developments of the auto-control technology and the fatigue experiment, analyzes the domestic situation of the experiment equipment, and the superiority of the computer-aided monitoring system of the tester, presents the research meaning and tasks.Computer-aided monitoring is related to auto-control, sampling theory, A/D and D/A conversion, data store and so on. Before the development of the system, the article describes the above-mentioned aspects, as the bases of the system development. The article emphasizes related auto-controlling technologies: open-100p and close-100p, and control mode of negative-feedback, the scatter and quantization of the simulate signal, the conception of A/D and D/A conversion and code/encode, the basic sampling principles of the simulate signal. The article introduces the operation method and process of the system by means of the load spectrum.In the following chapters, the article discusses the four aspects: the project of the system, structure, operation principles and program design, and expounds the process of the system development. Firstly, the article points out the differences between the old system and the new one on view from the operation principles and process, theinsufficiency of the old system and the superiority and of the new system as view from the function and practice. Through the comparison, the author confirms the necessary and feasibility of developing the system. According to the capability needs of the system and auto-control theory, the author confirms that the system is the close 100p negative feedback system.Secondly, the article recites the treatment process of the signals and data, and the operation principles of experiment tester loading parts. The singles are processed by the data Acquisition Card and PC. The data Acquisition Card is very important.In the development process, PCL-818L card is adopted by the system as the interfaces of A/D and D/A. The article introduces the card's capability and controlling modes. According to the application of the card in the system, the article discusses the card's structure, operation principles and related software and hardware, such as controlling clock, sweeping channel, the range of I/O signal and connecting modes.Then, the article introduces the circuits of the A/D and D/A, and the conversion method of the A/D and D/A. After the author discusses the card's capability and application, the article also expounds the processing course of data conversion when the data is read from the card and written on the card. Though processing the data that are read from the card, we can get the vibration frequency.After the methods of A/D and D/A were expressed according to the hardware and needs of the system, the article explains thelanguage environment and the program structure. The article introduces characteristics and superiority of the Delphi language in the system. By means of the combination of the interfaces and database, the system can be developed.To improve the system capability, the system stores and manages the data by database. The article explains several kinds of databases in Delphi language. Database Desktop is confirmed as the tools of establishing and managing database in the system, the method of establishing and managing the relative tables and the way of operating data are described, the application of the database storage technology also is introduced here in the system.Finally, the article explains particularly the process of the whole system by figures, words, program stream figures and parts of the program. Therefore, the whole system capability and operation mode are represented. Beca...
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