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MAKING THE CHANGE

From Standalone to Internet Appliance
by Edward Steinfeld

Start ý Internet Appliance Options ý Web Technology ý Cost and Options ý Web Server Inside ý Use Common Components ý Sources and PDF

WEB SERVER INSIDE

With a web server inside the instrument, you can design HTML graphics pages that look like the original hardware. Rotary knobs may be replaced with sliders and toggle switches with pushbuttons. CRT-like displays can be replicated using Java or ActiveX driven graphics. The entire human interface can be displayed remotely through a web browser. The pages for the web browser can be created using tools such as FrontPage or Dreamweaver HTML page-generation software.

You will have to write code to communicate among the web server and the various functions of the instrument. Much of this will consist of pointers to buffers and variables.

When completed, all of the front panel functions, controls, and displays can be made available to the operatorýs browser anywhere on the network where access to the instrument is available. That could be on the bench alongside the instrument or in an office two countries away.

REMOVE THE FRONT PANEL

Once you have an Internet connection to the instrument and the users have access to all front panel functions through their PCs, why keep the front panel? Front panels are expensive to build and the responsibility of the manufacturer to support. If the front panel can be replicated by HTML graphic pages on a web browser, all that may be needed on the front panel is an on/off switch.

Looking at the typical instrument, youýll usually find a set of knobs and switches. These knobs and switches are used to set up the device so it can measure or monitor external signals. They are used to set up the method of display of the monitored values. A front panel full of controls and displays is expensive to manufacture. It contains electromechanical devices that are usually hand-wired and contain expensive panel displays.

The cost of front panels for many instruments is about half the cost of the entire instrument. In many cases, the power supply of the instrument can be slimmed down if it no longer has to support the power-hungry video display. Making an instrument into an Internet appliance can give it added functionality at a fraction of the cost of the original instrument.

Customers can now provide the front panel through their web browser and select the type of computer best suited for their needs. That front panel can be wherever the user wants to work. With the functions available to them via the Internet, there can be multiple users monitoring the instrument with usually one user in control. The access to HTML pages with control functions can be limited by either user discipline or the manufacturer can include security features provided by the web server toolkit.

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