Peering into Your EDDL-based Field Devices

Advancing industry standards remains a vibrant activity in the process automation business. These standards foster faster market acceptance of new technologies by providing interoperability among many suppliers’ devices compliant to the particular standard.

InTech magazine has a nice update on one of these standards efforts, Electronic Device Description Language (EDDL) which is an extension of the International Standard IEC 61804-2. The article, EDDL allows interoperability for devices to constantly gather information, was written by ISA104 committee members, Christian Diedrich, Ludwig Winkel, and Emerson’s Jonas Berge and Terry Blevins.

The authors succinctly summarize the benefit of the EDDL standard for process manufacturers:

Using this technology, it is possible to provide an interoperable environment where distributed process control systems or handheld communicator can gather information available in modern automation sensors and actuators to configure, calibrate a device, diagnose problems, and provide data and alarms for user-interface displays.

They also note that the technology is pervasive in smart field devices:

For a user to garner Foundation Fieldbus (FF) certification, EDDL is a requirement, and it is the only device description language supported by the HART Communication Foundation. Because of that, virtually every Process Control Systems vendor worldwide supports EDDL. On top of that, Electronic Device Descriptions’ (EDD) are available for any FOUNDATION, HART, and some Profibus based field devices.

EDDL’s text-based data structure allows it to be platform independent:

EDDL provides a well-defined structure for supporting the most simple to the very complex field device. Since EDD’s are text-based interpreted by the host system, these files are independent of operating systems and control platforms. This structure allows the same EDD to have a common look and feel across applications, which reduces the learning curve and supports multiple host applications. Also, this enables field device additions to come into play without affecting the runtime stability of the control system.

The biggest benefit for users is that a consistent graphical user interface can be used to display the EDD information in smart devices, even when these devices come from different automation suppliers. The article states:

Graphical visualization supported by EDDL such as graphs and charts take full advantage of the capabilities of the host automation system. These capabilities can benefit engineers and maintenance personnel by providing a consistent look and feel during device configuration and maintenance.

Applications like Emerson’s AMS Device Manager and 375 Field Communicator provide graphical views of graphs, charts and calculations into devices supporting EDDL. These views also include complex instruments such as digital valve controllers, radar level gauges and multivariable meters.

Posted Wednesday, December 12th, 2007 under Foundation Fieldbus, Interoperability, Profibus.

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