OPC DataHub Uses Streaming AJAX and New Java Applets to Create Dynamic Web Pages

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The latest release of the OPC DataHub offers new web technologies including streaming AJAX for dynamic data in a web browser, and new Java applets for displaying real-time data updates in gauges and trend displays.

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The streaming AJAX and Java applet technologies are fundamentally different

The OPC DataHub from Cogent Real-Time Systems now provides even more ways to visualize and interact with real-time data in a web browser. Its new streaming AJAX Web Data Browser displays immediate updates to data from a wide range of sources like databases, spreadsheets, and OPC servers. This streaming AJAX technology can be used in conjunction with new Java applets for live displays of gauges, trending graphs, progress bars and other animated objects.

"These new technologies are ideal for visualizing real-time data on the web," said Andrew Thomas, President of Cogent Real-Time Systems. "Streaming AJAX reduces latency to near zero, while using minimal bandwidth and system resources. The live gauges and trending displays make it easy to see your system status at a single glance."

AJAX stands for Asynchronous Javascript And XML, a group of web technologies that allow a web server to send and receive data without having to refresh the page in the browser. Streaming AJAX delivers the data asynchronously to the page, following the "publish/subscribe" model of data connectivity. No polling is required, which means no latency--the data is updated on the page as soon as it changes at the source.

The OPC DataHub Java applets provide a way to animate a web page using real-time data. They connect directly to the OPC DataHub, and display the incoming data stream as a moving needle in a gauge, a dynamically drawn line in a trend graph, an expanding progress bar, or as numbers updating in a table or field.

"The streaming AJAX and Java applet technologies are fundamentally different," said Mr. Thomas, "but they can be used together. They complement the other OPC DataHub web technologies: HTML, XML, ASP, and polling AJAX. This wide range of choice lets you create efficient and visually appealing web page displays of real-time data with very little effort."

OPC is the leading protocol for data communications between industrial hardware devices and Windows software. The OPC DataHub is a memory-resident real-time middleware application that collects data from OPC servers and other sources, and redistributes it to any number of clients, such as Excel, ODBC databases, and web browsers. Now, with streaming AJAX and Java gauge and trend applets, the OPC DataHub gives unprecedented web-based data visualization capabilities to real-time systems of any size.

Founded in 1995, Cogent Real-Time Systems is the leader in real-time cross-platform data integration between Windows, Linux and QNX. Customers include the Bank of Canada, Cadbury Chocolate and the European Space Agency. Cogent leverages its experience in real-time data communications to provide the next generation of OPC products.

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ROBERT MCILVRIDE
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