Device description language to be a U.S. standard
ISA created a committee to work on making the IEC 61804-3 international standard on electronic device description language (EDDL) into a U.S. national standard. Standards committees often turn a national standard into an international one. In this case, ISA says, it’s important to republish the IEC standard as an American National Standard Institute standard “because some organizations might not recognize the international standard,” said proposal writer Terry Blevins, principal technologist at Emerson Process Management in Austin, TX.
The standard specifies a generic language for describing the properties of automation system components. The specified language is capable of describing device parameters and related dependencies; device functions, such as simulation mode and calibration; graphical representations, such as menus; and interactions with control devices.
“From a user perspective, this standardization is all good,” said Nick Sands, an ISA Standards Board member and a process control technology manager at DuPont in Newark, DE. “Having common device descriptions is one step toward simplifying the Gordian knot of updates for a complex process control network,” he said. “Flash this, upgrade that, download everything. It’s not as easy as saying‘asset management.’ ”
EDDL and the device-related electronic device description (EDD) see use in industrial automation applications, which could include devices such as generic digital and analog input/output modules, motion controllers, human machine interfaces, sensors, closed-loop controllers, encoders, hydraulic valves, and programmable controllers.
IEC61804 standard gained approval as an international standard around two years ago and has entered its first maintenance cycle. In the current standard, Part 2 describes the function block model and EDDL. As part of the maintenance cycle, developers are breaking Part 2 into Parts 2 and 3. Part 2 will be the function block model and Part 3 the EDDL. “The EDDL update contains many improvements in support of graphical representations, such as menus and trends,” Blevins said. “This standard specifies the semantic and lexical structure in a syntax independent manner. It’s also possible to use the semantic model with different syntaxes.”
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— Richard Phelps, senior editor, Control Engineering