Remote Instrument Control Through Internet
description
Transcript of Remote Instrument Control Through Internet
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
• What is Virtual Instrument?
AD/DA CardGPIB Card, etc.
Software
Virtual Instrument
Development of RICI using CGI
• Virtual Instrument - Sine wave signal generator
Development of RICI using CGI
• Start page • Result page
• Demonstration
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
• 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
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
ConclusionDifference between CGI method and Java method
Item CGI method Java methodProgramminglanguage
any language: C, Perl, Tcl/Tk,shell script
Client side: java ;Server side: anylanguage
platform dependent yes noexecution server client and serverexecution speed fast faster
Conclusion
Item CGI method Java methodhardware requirementof client PC
no must be powerful enough torun java applet
software requirementof client PC
graphical webbrowser
graphical web browser withJava support
connection per session basis continuous
user interface friendly friendly and flexible
Difference between CGI method and Java method
Conclusion
Item CGI method Java methodapplication for using instrument with few
parameter and infrequentlyadjustment only, i.e., voltagemeasurement.Not applicable for PID tuning
any instrument
compatibility any web browser, even lynx not good, alwaysneed latest graphicalweb browser
Future Work
• authentication
• encryption of transmission
• integration with Computer Supported Cooperative Work
• potential application in industry