Emerson’s Dale Perry and Jonas Berge teamed up for a look at EDDL (Electronic Device Description Language) technology from a pressure measurement device perspective in a recent Industrial Automation Asia article, Pressure Transmitters: EDDL Equals Easy.
Their summation describes well why you might have an interest in this interoperability standard:
Given the breadth of transmitters and other field devices throughout process facilities, interoperability is essential for integration and ease of use. EDDL is the key to interoperability in a digital plant architecture as it merges functionality of devices using HART, Foundation fieldbus, or WirelessHART into the same single software structure so they can be managed together from a single dashboard.
Dale and Jonas describe the problem the enhanced EDDL standard addresses from the perspective of a pressure transmitter supplier:
Historically there was no display standardisation. The dilemma was that the pressure transmitter manufacturer could not dictate the system display or accessible transmitter functionality on a system.
It was primarily left up to the system vendor to create specialised screens that may or may not have included all the specialised functionality of pressure transmitter. It was not uncommon that devices that did not come from the system vendor itself was at a disadvantage.
The article highlights some of the information presented by Rosemount pressure transmitters via enhancements to the EDDL standard. The authors note that before these enhancements:
…there was no graphics for quick visualisation of the pressure transmitter diagnostic status nor could you look at the current PV and tell what the pressure was two minutes ago. And if the device had multiple variables there would be multiple numbers to look at and do math and correlation in your head.
The article displays and describes screen captures as seen in AMS Device Manager that supports enhanced EDDL including: trend charts, device diagnostic summary status, graphical gauges, detailed diagnostics, and even specialized charts that device suppliers can create. One Rosemount pressure transmitter example is a standard deviation chart showing process noise. In this case, it typically signals a plugged impulse line.
Dale and Jonas sum up the article by defining the responsibilities for both the device and software application providers:
Although the transmitter manufacturer controls what information is made available from the transmitter and how it is laid out on the screen, the look & feel details such as the appearance of buttons as well as activation of the help, printing, acceptances of changes, and comparison is handled by the device management software ensuring all devices work consistently regardless of manufacturer, type, or protocol.
Update: I updated the link to a PDF version of the article.
