An Update on EDDL and FDT

There are two sets of standard tools commonly used for reading, interpreting and displaying digital information from field devices—EDDL and FDT.

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EDDL stands for Electronic Device Description Language, and FDT represents Field Device Tool. These software tools play a vital role in facilitating preventive maintenance and helping to turn digital automation into a nearly plug-and-play affair. They can coexist in the same plant.

EDDL has the longest history, going back to 1992, when, as DD, or device description, it was launched as an aid to device set-up and diagnosis. Widely adopted, it became an international standard (IEC 61804-2 from the International Electrotechnical Commission) in 2004, when the name EDDL was hung on it.

FDT was launched in 2003 and was officially chartered in Diegem, Belgium, in 2005 as the FDT Group (www.fdtgroup.org). Its goal is to provide a standardized communication interface between field devices and systems that is independent of the communication protocol and the software environment of either the device or the host system, allowing any device to be accessed from any host through any protocol.

Meanwhile, in 2006, EDDL launched an updated version of its standard (IEC 61804-3) with enhanced graphics capabilities. The new graphics give device manufacturers considerable control over the content and structure of the display while still ensuring a consistent look from device to device. “For instance, the device manufacturer decides the display shall contain a button,” says Jonas Berge, director of PlantWeb consulting in Singapore for automation vendor Emerson Process Management (www.emersonprocess.com), Austin, Texas. “The system decides the size and color of the button. This way, the device vendor can provide access to all functionality in the device, yet the display from one device to the next is consistent.”

Much has been made of the similarities between EDDL and FDT, notes Phil Marshall, vice president of sales for Hilscher North America (www.hilscher.com), an automation supplier in Lisle, Ill.But “one of the differences is that FDT can be used to develop a universal network Master configuration tool,” Marshall says. “This capability has allowed Hilscher to create a universal network tool that original equipment manufacturers can embed into their applications with several weeks of work. With Sycon.net embedded in their control programs, end-users are able to set up their networks and dynamically share the configuration data, including tag names, with the host program. This allows any OEM to provide a level of usability for many different networks that has only historically been achievable by the major players for their own core network technologies.”

Concise, timely information

Meanwhile, Scott Wilkerson, senior product manager for supplier Flowserve Corp., in Lynchburg, Va., notes, “We have software to capture continuous device testing. With advanced diagnostics and a graphical user environment, users can take a proactive approach to service with predictive maintenance programs rather than periodic. We support both EDDL and FDT—the technology that makes it appear to the user. It will be viewed differently depending upon which vendor’s software is used, but that’s just a preference of the user. Both technologies are critical to passing information to the user in a concise, timely manner.”

The FDT technology also uses something called a DTM or device type manager. Shannon Foos, who is North American Marketing Director for the FDT Group, as well as a Process Segment Manager at vendor Rockwell Automation Inc. (www.rockwellautomation.com), in Mayfield Heights, Ohio, says the key recent news is that FDT has achieved IEC standardization as IEC 62453.

Foos likens FDT to a Web browser, with DTM likened to a Web page. “The benefit of the FDT frame is that device information is presented to the user the way the vendor anticipated in a usable or consistent way. DTMs work for the entire lifecycle of the device, from engineering, project planning, parameterization and  ongoing maintenance to real-time diagnostics and predictive maintenance.”

Gary Mintchell, gmintchell@automationworld.com, is Editor in Chief of Automation World.

FDT Group
www.fdtgroup.org

Emerson Process Management
www.emersonprocess.com

Hilscher North America
www.hilscher.com

Rockwell Automation Inc.
www.rockwellautomation.com

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