Thin Client Approach to HMI

(Sidebar to "A Better View of the Plant" from the January 2008 issue of Automation World)

Much of the move to new human-machine interface (HMI) technology has been accompanied by a shift to thin-client systems. Instead, the processing is done in a server, often with redundant backup, that sits in a protected environment. “The whole move to client-server technology is having an impact,” says Mark Hobbs, product manager for FactoryTalk, at vendor Rockwell Automation Inc., in Milwaukee. “Our users can develop a common application across the entire enterprise in a common design environment that can be displayed on a four-inch screen to a 15-inch HMI with a common look and feel.”
Using a redundant server system that is protected from the harsh environment of plant machinery can hedge against costly crashes. “We’re utilizing redundant servers that go to thin clients as screens,” says Jim Compson, a systems integrator from Advanced Engineering Inc., in Franklin, Tenn., which works with Siemens products in the paper-and-pulp industry. “The server publishes Web pages so we can show more up-to-date information to more people.” One of the reasons for using redundant servers is that the data is protected. “If one server crashes, the other one runs,” says Compson. “Also, if you spill 500 gallons of water on the plant floor, you destroy a $1,000 thin client, not a $10,000 computer.”

ARC Advisory Group Inc., in Dedham, Mass., offers these recommendations for adopting the thin-client systems for HMI software:

• Manufacturers should evaluate the three types of thin-client HMI approaches—local Web, remote Web and mobile Web—selecting the approach best suited to individual visualization needs.

• They should leverage thin-client technology as one method of using the Internet to link manufacturing plants to their suppliers, customers and distributors.

l• All processing should be performed on the server or devices enabled with Web server software, and only required information such as screen updates should be delivered to the client station or local device.

For an informative Webcast on integrating real-time information, visit

 To see the main story this sidebar was taken from - "A Better View of the Plant" - please visit

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