Transcript 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
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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
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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