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Remote Instrument Control Through Internet Gu Feng July, 1998 Content • Introduction • Development of RICI using CGI • Development of RICI using Java • Conclusion • Future Work Introduction • • • • • Possibility of RICI Unified user interface Ease of usage Interactivity Benefit Introduction • System Structure Development of RICI using CGI • CGI is an acronym for the Common Gateway Interface, which defines the standard way in which external programs should communicate with a Web server. • Typical procedure of controlling a remote instrument – Using any internet browser to connect to the web site where the instrument is located. – The web server will provide a web page, which enables users to enter desired instrument parameters and submit them to the web server. Development of RICI using CGI – The CGI program on the web server will determine whether the entered parameters are acceptable or not. – If the entered parameters are acceptable, the CGI program will generate commands and transfer the commands to the Lab PC to which the instrument is connected and controlled. – The Lab PC will execute the commands and acquire output of the instrument. Development of RICI using CGI – The acquired data will be transferred from the Lab PC to the CGI program. – The CGI program will then translate the acquired data to HTML format and send them to the remote user. Development of RICI using CGI AD/DA Card GPIB Card, etc. Virtual Instrument Software • What is Virtual Instrument? Development of RICI using CGI • Virtual Instrument - Sine wave signal generator Development of RICI using CGI • Demonstration • Start page • Result page Development of RICI using Java • Java – – – – – – platform independent compile once, run anywhere java applet can run on client side more flexibility, interactivity and immediacy continuous connection between client and server more friendly and easy-to-use user interface Development of RICI using Java • Typical procedure of controlling a remote instrument – Using any internet browser to connect to the web site where the instrument is located. – The web browser will automatically download a java applet and run it. – The Java applet will establish a TCP connection with the server program running on web server. Development of RICI using Java – The user will enter desired parameters and click <run> button. – The java applet will send the parameters to the server program. – The server program will determine whether the entered parameters are acceptable or not. – If the entered parameters are acceptable, the server program will generate commands and transfer the commands to the Lab PC to which the instrument is connected and controlled. Development of RICI using Java – The Lab PC will execute the commands and acquire output of the instrument. – The acquired data will be transferred from the Lab PC to the server program. – The server program will then generate a GIF file according to the acquired data and inform the java applet that the GIF file is ready. Development of RICI using Java – The Java applet will fetch the GIF file and display it on the user’s screen. – To get a new result, the user just need to change the value of parameters and click <run> button. Development of RICI using Java Demonstration - Start page Development of RICI using Java Demonstration - Result page Conclusion Difference between CGI method and Java method Item Programming language CGI method Java method any language: C, Perl, Tcl/Tk, Client side: java ; shell script Server side: any language platform dependent yes no execution server client and server execution speed fast faster Conclusion Difference between CGI method and Java method Item CGI method Java method hardware requirement of client PC software requirement of client PC connection no graphical web browser per session basis must be powerful enough to run java applet graphical web browser with Java support continuous user interface friendly friendly and flexible Conclusion Item CGI method Java method application for using instrument with few parameter and infrequently adjustment only, i.e., voltage measurement. Not applicable for PID tuning any web browser, even lynx any instrument compatibility not good, always need latest graphical web browser Future Work • authentication • encryption of transmission • integration with Computer Supported Cooperative Work • potential application in industry