imple smart pressure and temperature measurement transmitters could be configured without need for graphics. However, more sophisticated (complex)

devices such as valve positioners, variable speed drives, machinery health monitors, and radar level transmitters now common in process industry plants require advanced graphical setup and diagnostics.

By upgrading software to the new enhancements of the international standard IEC 61804, plant personnel can make their devices, both old and new, simple and advanced, easier to use than ever before.

Similarly, predictive diagnostics can be better integrated into daily work practices by displaying them to the

right persons. This is achieved without making system management more difficult with respect to staying current with new devices and Windows versions.

This article recommends a best practice for device integration outlined in the NAMUR NE 105 recommendation by upgrading to a single standard: IEC 61804-3.

Meet The RequirementsBack in 1992, the original Device Description (DD) technology made it possible for the first time to configure many types of smart transmitters from different manufacturers using the same universal communicator rather than one proprietary communicator from each

42  industrial automation asia | Oct/Nov 2008

instrumentation & measurement

EDDL with enhancements enables a single tool for simple and sophisticated devices including advanced setup and diagnostics. By Jonas Berge, director, PlantWeb consulting, Emerson Process Management

marchingmainstreamEDDL:

Graphical elements in EDDL with enhancements.

EDDL (D

D) cre

ated

FDT/

DTM cr

eate

d

EDDL (D

D) sta

ndar

dized

NAMUR N

E 105

reco

mm

endat

ion

EDDL Coo

perat

ion Te

am fo

rmed

EDDL with

enha

ncem

ent s

tand

ardize

d

FDT

grou

p joins

EDDL

Cooper

ation

Team

1992 1998 2004 2006

Device integration technology time-line.

The original DD technology, dating from 1992, lacked the ability to display and store graphics and thus did not meet the requirement for support of full device functionality. Other solutions had the graphics but did not meet the other NE 105 requirements. New EDDL with enhancements supports graphics while preserving all the advantages of original DD.

The enhancements to EDDL were jointly developed by engineers from the Fieldbus Foundation, HART Communication Foundation, Profibus Nutzerorganisation eV (PNO), and OPC Foundation to meet the requirements of NE 105.

Full Device FunctionalityMost plants today have sophisticated (complex) devices like control valve positioners, machinery health transmitters, variable speed drives, and radar level transmitters that must be managed from the same software as simple pressure and temperature transmitters.

Since the original DD did not have graphics or persistent data storage, other solutions had to be developed to support the more sophisticated devices. Systems mixing multiple technologies were harder to manage and had added limitations.

EDDL solved this with enhancements providing rich graphics, a menu system, persistent data storage, and ability to handle data dependencies. Wizards and calculations are available to make complex procedures such as setup and calibration easy, reducing mistakes, and at the same time make sure all technicians perform these tasks the same way with greater consistency.

Charts and graphs with multiple simultaneous values as well as table grids allow advanced setup and advanced diagnostics of sophisticated (complex) devices. The enhanced menu system makes navigating large sets of parameters much easier.

Manufacturers impart their device and application know-how to users in the form of text, images, and context sensitive help to make their devices easy to use. It is the device manufacturer that decides on the content and structure of the information displayed to make their devices user friendly while all information is presented.

EDDL with enhancements enables a single tool for simple and sophisticated devices including advanced setup

44  industrial automation asia | Oct/Nov 2008

iNstrumeNtatiON & measuremeNt

and diagnostics. Thus EDDL is suitable for all phases of the life-cycle including maintenance and operation. Users see the full, rich, and familiar Windows graphical presentations on their computers.

EDDL makes devices fully interoperable, and since they are displayed as intended by their manufacturers, nothing hidden. Devices that fully support EDDL with enhancements need no additional software.

Consistent Look & FeelDevice manufacturers must be allowed to determine how information and features in their devices are organised in displays: content and structure. Previously however, device manufacturers used different icons, different button locations, and different color schemes etc for their displays.

The variations resulted in inconsistencies between devices, which made life difficult for technicians who had to manage a mix of devices from different manufacturers using different protocols.

This dilemma is solved using EDDL, which allows manufacturers to define the display content and structure of a device, but not look and feel details. Therefore, colour coding for parameterisation status such as ‘writable’, ‘read-only’, ‘changed but not downloaded’, and ‘compare mismatch’ is defined by the device software and thus identical for all devices regardless of protocol, manufacturer, or type.

Moreover, the look and feel are the same as for the entire control system and asset management package. EDDL displays devices graphically but without undue creativity.

The look and feel of buttons to accept parameter changes, access help, and print are the same for all devices. Consistent use of option lists, check boxes, and multiple status indication are also standardised by EDDL.

Tools to pan and zoom for trend charts and waveform graphs work the same way for all devices. Gauges, bar-graphs, and histograms are the same for all devices regardless of protocol, manufacturer, or type.

Device displays make use of a standard multilingual EDDL dictionary of common phrases displayed in user interaction such as prompts and help text. Furthermore, IEC/TR 61804-4 includes a standard root menu for navigation.

As a result, EDDL-based tools are easy to learn. Working with a mix of devices soon becomes intuitive thanks to the consistent look and feel, nomenclature, and messaging.

The consistent look and feel of EDDL are intrinsic properties of the technology not matched by earlier attempts to style guides.

Investment ProtectionA control system needs to operate for 15 years without having to be replaced. Therefore:• ItshouldnotbenecessarytoupgradeWindowsversion

when a new device type or version is integrated to the system.

Oct/Nov 2008 | industrial automation asia  45

Consistent look and feel across all manufacturers, device types, and protocols.

• Systemsupport foranexistingdeviceshouldnotbe lost when Windows is upgraded or when service packs or hot fixes are installed.

• Support for an existing device should not be lost when device management software is upgraded.

• It should not be necessary to upgrade devicemanagement software when a new device type or version is integrated.

Device integration solutions using Windows software interfaces are coupled to fast-paced changes of the IT revolution.

As an independent standard IEC 61804-3, decoupled from Windows, EDDL is intrinsically unaffected by rapid obsolescence in the IT world. EDDL files for new devices are independent from, and therefore compatible with, old Windows versions, patches, .NET framework, and service packs.

New Windows versions, patches, .NET framework, and service packs are equally compatible with EDDL files for old devices. New versions of device management software are compatible with EDDL files for old devices. DD files without graphical enhancements are supplied together with enhanced EDDL files to support older device management software.

EDDL staves off obsolescence because an EDDL file is a document, not software. There is:• NoneedtoupgradeWindowsversionorinstallpatches,

.NET framework, or service packs to support new device versions.

• Noneed towait fornewEDDLfilesbeforeWindowsupgrade, patches, service packs, .NET framework or upgrade.

• No need towait for new EDDL files before devicemanagement software upgrade.

• Abilityforfuturedevicestobeintegratedintoexistingdevice management software.

There should be few surprises associated with a Windows language version/edition. Plant personnel can quickly adopt any new Windows version and benefit sooner. Files created for devices in 1992 still work on systems shipped today, showing that EDDL protects the control system investment.

No Software Version ConflictsPlants cannot afford the risk of new versions of software interfering with control systems or even device management software. This is why third-party software is never allowed to be installed on a DCS. Nor are device integration solutions that rely on device drivers allowed on a DCS, since each driver is actually third-party software.

For this reason, device diagnostics had to be done from a console that is not integrated with the DCS operator station, so checking diagnostics was not a natural part of daily operations.

EDDL solved this because the file is compressed text, and no software is installed to support a device. Thus it does not interfere with the DCS. Thus, EDDL-based diagnostics can be totally integrated with the DCS. Moreover, because each version of every device type has its own unique file, integrating a new type or version of device does not interfere with existing devices.

In an integrated system, EDDL enables work to be done from a single ‘dashboard’. That is, there is no need to change seats to diagnose a device failure. Device diagnostics can be done from the operator workstation. Operators can differentiate device problems from process problems and take appropriate action such as putting a loop into manual control before the process is affected. Then, the operator can call on a technician in the field with the details so that the problem can be fixed.

Easy Device UpdateNew types and versions of devices come into plants as part of improvements and replacements all the time, so it must be easy for technicians to integrate them into the system.

Some earlier solutions required installation of driver software to support a new device type or version. The technician who commissioned a new device also had to be a bit of an IT expert to handle installation prompts such as license agreement, disk space, replacing existing files, etc. He also needed an 'administrator' level password, but installation was still time-consuming.

EDDL solves this as well because the file is not a programme or driver so there is no need for the technician who commissions a new device to install software. New EDDL files are downloaded from the device manufacturer, then simply copied and pasted onto the system, like a document. Because EDDL files are very small, they can even be emailed as an attachment if need be. Moreover, EDDL files for existing devices are never removed, thus ensuring robustness.

Beyond mere detection, EDDL supports automatic association of a device to its EDDL file without manual

Device diagnostics integrated with plant operations.

46  industrial automation asia | Oct/Nov 2008

iNstrumeNtatiON & measuremeNt