SEPARATE PRESS releases from the Fieldbus Foundation and Profibus International arrived last month, both announcing agreement between FF, PI, the Hart Communication Foundation and the OPC Foundation to develop further the Electronic Device Description Language (EDDL). Three of the organizations, FF, PI and HCF, had originally cooperated in combining their three slightly different DDL specifications to create a single harmonized EDDL with which they were all separately compatible and which was embodied in the IEC 61804-2 standard which was ratified early in 2004.
That success was followed up with another cooperative venture to enhance EDDL. Completed last autumn, the enhancements have been incorporated into the respective Foundation fieldbus, HART and Profibus technologies and are now being incorporated into the OPC Unified Architecture specification. The enhancements, which will eventually be incorporated into IEC 61804-2, extend interoperability to the HMI and diagnostic data level. They focus in particular on device data organization, graphical visualization consistency and support for persistent data storage while ensuring backwards compatibility with existing devices.
Joint Maintenance Team
Under the latest agreement, a joint maintenance team which had been set up at this year’s Hanover Fair 2005 will further develop EDDL technology, creating a test specification and developing a general test procedure covering all extensions to the IEC standard. The agreement also establishes a steering committee with delegates from the four user organizations to determine further activities.
Some 1,000 field device types from more than 100 manufacturers are described by EDDL and it is estimated that more than 15 million FF, Hart and Profibus field devices based on EDDL have been installed worldwide. Electronic Device Descriptions (EDDs) created using EDDL are ASCII files and are therefore Operating System and HMI-neutral.
Fieldbus Foundation president and CEO Richard Timoney believes this latest cooperation project will protect industry investments in EDDL by enabling additional enhancements to the IEC standard. “The Fieldbus Foundation strongly supports the effort to advance IEC 61804-2 . . ,” he said. “The EDDL standard assists suppliers faced with developing intelligent instrumentation that is compatible with multiple protocols. The technology streamlines the device development process and lowers the cost of bringing new products to market.”
Whether by coincidence or design, the EDDL releases followed close on the heels of another release from Profibus International, announcing that it had transferred further development of FDT technology to the FDT Joint Interest Group (FDT JIG), which has in turn completed and published a revised specification. PI remains a cooperation partner of FDT JIG and will continue to be involved in all reviews of the new specification.
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