The Research Of Network Accessing Technology On LabVIEW Measurement & Control System

As the G Language graphical development tool for implementing Virtual Instrumentation (VI), Lab VIEW has been one of the most popular solution for creating powerful, flexible, well-structured, cost-effective and friendly HMI (Human-Machine Interface) measurement & controlling system. However, although most PC can be easily networked into Intranet or even Internet, most current LabVIEW applications are run on single PC without making use of the advantages of network.This thesis researches deeply and comprehensively the applications of the network functions of LabVIEW, based on extensive reading and intensive analysis of LabVIEW manuals, application notes and hands-on development experience.After summarizing the LabVIEW G Language programming, we research three network communication mechanisms of LabVIEW: the TCP/IP functions, the VI Server mechanism and the DataSocket technology. We analyze each mechanism in detail and develop related G programs to show their functions.In comparison with other communication mechanisms, DataSocket and DSTP protocol are the most important standards for real time VI data communication presented by NI. We also discuss the security considerations of DataSocket and introduces the support to OPC with DataSocket in LabVIEW. Based on DataSocket API and DSTP protocol, we develop the programs of ActiveX controls and Java Applet, which can be run in Web browser to access remote VI application. The Java Applet is developed with DataSocket JavaBean and third-party Interface components at IBM VisualAge for Java, We regard it as a way for cross-platform interactive access solution in the future.We also research the support of ActiveX in LabVIEW, presents the main techniques for creating ActiveX Automation Client VI and client application for VI as a ActiveX server.We introduce two ways of publishing HTML documents from Lab VIEW and the configuration and usage of LabVIEW built-in Web server, presents a "One Divides Into Two" strategy for practical Web publishing in LabVIEW applications, and also discusses how to embed the Web browser ActiveX controls in VI. Since XML has many advantages over HTML, we also discuss the possible application of XML in LabVIEW and implementing strategy of using Java Applet to parse VIML documents.We develop a Demo LabVIEW application for a measurement & controlling project, and impletment its network application.Finally, we support the future trend of seamless integration of VI applications into Information network, and emphasize the need for researching e-Business architecture and emerging technology such as Web Service which will influence the next step of LabVIEW.