Networked Test Systems And Real-time Study

With the modernization of science and technology and the development of a large scale of industry and agriculture, there exists distributed automatic testing systems that implement localized, remote and networked test,which derives benefits from rapid development of computer, network and communication technologies, and combines automatic test with computer and communication technologies. "Network is instrument" describes the tendency of networked test. Today, networked test has transcended the limits of space, which brings about quality leap compared with traditional test systems. Networked test technology is comprehensive and inclusive. This thesis studied systematically and deeply on the test technology from the point of view of models, real time and building technology of networked test systems.The thesis first arguments the architecture of networked test system, then designs a hierarchy model with extensible and flexible structure, and then discusses the compatibility of different types of measurement nodes at the same level and seamless connection of test and control network to information network. A new WWW network computing platform and a new database management system are presented based on CORBA/JAVA object Web technology.The real-time of system is studied. To begin with, Feasibility of networked test with Ethernet is demonstrated by modeling of CSMA/CD protocol of standard Ethernet and analysis of Ethernet performance, especially for network time delay and real time test experiment. And analyses the problems of networked test with Ethernet and proposes the solution. Then efficiency of transfer over Internet is analyzed. Two main measures for time delay optimization: traffic configuration optimization and route selection optimization are used for reducing average transfer time delay. Estimated model for 1 to 1 network performance estimation, measurement method and estimation algorithm for network performance evaluation are proposed. Inaddition, real time multimedia service technology based on network protocol and synchronization technology for improving real time of system clock are also presented. The third part of the thesis studies the building technology of networked test system. Starting with networked intelligent field equipment --- architecture of networked instrument and networked sensor and basic hardware and software, we discusses embedded wire networked transducer based on IP and IEEE1415.2 and wireless networked transducer based on IEEE1415.2 and Bluetooth protocol. Networked instrument is divided into two categorizations: embedded network instrument and computerized network test instrument (virtual instrument). Intelligent field equipment at the bottom level is networked for openness, general use, interchangeability, real time and reliability. Next, we have discussed reliability and fault diagnostics technique for networked test system. A comparison experiment is carried out which based on the physical redundancy and analytical redundancy of the minimum square residual analysis. And LAN faults are diagnosed with probabilistic distributed faults diagnostic algorithm. In the end, we show how to set up networked test systems and exhibits wide application forground of networked test technique in military and civil use with three application cases—— networked test system based on CORBA/JAVA, measurement on demand system and measurement and control system of a weaponry equipment.