SCADA starts WEB WEAVING

Industries with widespread, remote monitoring requirements - such as the water supply and offshore oil industries - have benefited greatly by installing supervisory control and data acquisition (SCADA) systems, despite the cost of the dedicated communications networks needed to link all the sites together. But those benefits should soon be available to all, and at very little extra cost, following an upsurge of interest in the Internet and the world-wide web by many SCADA suppliers.

At last October's ISA Show in Chicago, Sun Microsystems set the ball rolling by announcing plans to work with hardware and software developers - including major control companies such as Elsag Bailey, Honeywell and Foxboro - to deliver real-time process control applications based on its Java programming system.

Increasingly familiar to `net surfers', Java is the embedded operating system that is automatically downloaded over the Internet from supporting web sites. Independent of the hardware platform being used to access the Internet (or intranet), applications written in Java are downloaded with web pages (as `applet' attachments) and put into action by the web browser software (such as Netscape) being used to view the page.

According to Mark Groves of SCADA supplier Intec Controls (developer of the Paragon TNT system), this ability to download what is known as `executable' content introduces a large number of possibilities for presenting live data from process plants. `Java applets can read information from a SCADA product and present that data within an HTML (hypertext mark-up language)-developed page displayed on your web browser. Information cannot only be displayed, but the applet can accept user input and update points over the Internet back to the SCADA system. Real-time trends, alarm and event lists, as well as real-time values, can be mixed on the same HTML page, much like a typical plant mimic.'

Intec is one of several SCADA suppliers seriously addressing these developments and the next release of Paragon TNT will support HTML and Java technologies. First off the blocks, though, could be PC Soft with its integrated Java-based WizBrows, due for release in the first quarter of the year.

Using a standard Internet browser, the WizBrows software integrates with PC Soft's popular Wizcon SCADA package to allow remote and mobile operators to view their control applications. The advantage of Java here, says PC Soft, is that screen updates are event-driven and need very little bandwidth, so even `wireless' users can monitor their processes remotely.

An encouraging sign for the future of such web-based systems is that support for the technologies is already on the market. For example, at the UK FieldComms exhibition, also last October, Io launched `interGate' which makes it possible to use a web browser to access real-time data from plant or field. The version on show interfaces LonWorks-compatible devices - widely used for building and industrial automation - into a rugged `micro web server' capable of generating HTML reports.

Based on a compact 386EX target computer with a modem, and a LonWorks interface from Io's IoNet system, the server costs under £1000. Io also offers stripped-down version for connection into a corporate intranet via local or wide area networks (LAN/WANs).

Also already available in the UK, from Visorgraph, is Web@aGlance, Intuitive Technology's software that enables engineers, or anyone else with access to a corporate intranet, to obtain data from plants anywhere in the world. The Standard Edition - with which browers can view data using Netscape or Microsoft's Explorer, and use an ActiveX control for applications development - has now been enhanced via a Professional Edition. This adds an animation editor to create process diagrams and link data points with graphic objects. @aGlance/IT servers are available for many leading DCS and SCADA systems, and there is a development kit for other servers.

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