Intelligent device management with EDDL

EDDL technology was specifically designed with the process industry in mind. EDDL is an integral part of the bus protocols used in process industries: HART, Foundation fieldbus and Profibus. For instance, EDDL is required in systems that support the Foundation fieldbus function block programming language. It is a complete process industry solution spanning transmitters, analysers, valves, variable speed drives, motor starters and MCC (but not motion control), and covers devices used in both process control and process safety. The graphical enhancements possible with EDDL include waveform plots, trend charts and dial gauges that are common in process control. To meet the needs of the process industry, the standard EDDL dictionary contains common terms and phrases used in process instrumentation to ensure technicians see consistent software prompts and other information.

Process instruments, such as radar level transmitters, are set up and calibrated in the field, and in many process industries this requirement is met by readily available handheld communication devices. EDDL is the best fit for process control; therefore, it is also used in the DCS world of integrated systems. EDDL remains independent from underlying gateways and interface cards, so one EDDL file fits all systems.

Interoperability

EDDL has been the de facto industrial standard since 1992 and an international standard since 2004. It was enhanced by a partnership between the Fieldbus Foundation, HART Communication Foundation, Profibus Nutzerorganisation eV (PNO) and OPC Foundation to develop graphics enhancements for the IEC 61804-3 standard. Plants now have the freedom to choose systems, devices and portable tools from their preferred vendors. EDDL is the key to interoperability between manufacturers, using different protocols and different versions, to unlock capabilities, access data and unleash the full capability of systems and devices as per NAMUR NE 105 recommendations.

Hundreds of companies have developed products around the EDDL technology. EDDL supports radar level transmitters and many other devices offered by many manufacturers: simple transmitters, analysers, valve positioners, variable speed drives, machinery health transmitters and bus diagnostics. EDDL solves an existing problem by allowing device management through a single, universal software.

As an industry standard, EDDL is the basis for control system engineering stations, handheld field communicators and device management software that is a part of the asset management solution, and for workbench laptop software. EDDL is the only technology in use in all these tools. It is possible to use EDDL in the DCS engineering station because it is not software, and to use it in handhelds because it is not locked in to the Microsoft Windows platform.

Thanks to this full suite of tools, EDDL supports all phases of the life cycle: system configuration, commissioning, operations and maintenance. Although performing all of these tasks is possible with one kind of tool, it is probably not ideal. Different tools better suit each phase of the life cycle. System configuration is best done from the DCS; commissioning with a handheld communicator; operations from device management software that is part of an asset management solution; and maintenance from a laptop in the workshop.

Many manufacturers have developed products around the EDDL standard so that support for the infrastructure, tools and tasks are already available. This includes laptop software that use PCMCIA interface cards for FF and USB modems for HART — even the old RS232 modems for HART are supported. Device management software can either tap into the I/O subsystem of modern control systems or to multiplexers in use with older systems. All these tools built around EDDL provide a complete solution to the varying needs of each phase of the life cycle.

EDDL is at the core of the digital nervous system for intelligent device management software. These applications provide functions such as on-screen display of the device data, printing of reports, exporting device date to Excel and data availability for other applications through OPC or XML/MIMOSA.

Many services have grown up around the EDDL technology as it is an interoperable standard. The HCF, FF and PNO, as well as manufacturers, furnish interoperability tested EDDL files for fast and easy download for plants that receive a new type or version of device. The bus organisations provide interoperability testing, which is a form of quality assurance for plants using the devices, and training on these bus technologies includes EDDL as part of the curriculum.

Integrated device diagnostics

A digital plant architecture that uses the power of field intelligence to improve plant performance must deliver accurate, actionable information to the right person in time to make a difference. But who is the right person? When a device fails, operations first needs to take evasive action. They may have minutes or hours to act before the process is affected. The responsibility for fixing the device then falls to the maintenance team. Both maintenance and operations need to know about device failures, albeit for different reasons.

In the past, capturing device diagnostics was often not done. The few systems that did capture diagnostics often displayed it only on a separate maintenance station that was not continuously attended and, therefore, the information was not acted upon. Evasive action was not taken, so the process was allowed to go off-spec or shut down. The device also was not repaired in a timely manner. Therefore, there was a need for a new solution that allowed a timely response based on actionable information.

EDDL is now used to overcome this problem. EDDL files are compressed text, not software, and are non-intrusive and, therefore, permitted to be loaded on DCS servers and workstations without affecting the robustness of the system as per NAMUR NE 105 requirements. It is now possible to integrate annunciation of device alarms, such as radar level transmitters, on operator stations and allow the operator to call up detailed diagnostics as suggested in the NAMUR NE 91 recommendation. EDDL is the platform for enabling device diagnostics for incorporation into daily work processes, so that operators can act before the process is affected and technicians can begin repairs sooner. EDDL is the way to get critical diagnostics to operators thus enabling a reduction in downtime. When plants perform maintenance more effectively, they operate with an advantage.

EDDL enables intelligent device management, such as better and easier device set-up, as well as predictive diagnostics that are integrated with control system operator stations. While other technologies can display diagnostics and set-up information, these diagnostics cannot be integrated into the primary user interface — the DCS operator console. Moreover, keeping the system current with new versions is more difficult with other technologies — as the plant utilises new device types and versions, the system may become ineffective and fall into disuse. EDDL-based software enables both speed and convenience in updating new devices and versions which other solutions cannot match.

Ease of use

The EDDL file comes bundled with the device so there is no need to purchase a driver, or licence key, and the EDDL file is interoperability tested with the device as a package. Software comes ready to use and preloaded with EDDL files for hundreds of different device types and versions from many manufacturers which use different protocols. Keeping the software current with new device types and versions as they arrive at the plant is easy — simply download a copy of the new EDDL file from the manufacturer's website or a corresponding bus protocol organisation’s website. An EDDL file is small so that descriptions for many devices can even be emailed as a simple attachment, thus saving time. This ease of administration gives plants more independence and reduces the reliance on system vendor services. As the manufacturer identifies product usability issues, they design EDDL solutions which are easy to deploy. EDDL offers a robust mechanism for managing device and EDDL file version changes, so making product improvement transitions represent a low risk.

No need to retrain

New EDDL enhancements do not require a change of skills or procedures because administration of the files is similar to the traditional DD files used with HART, Foundation fieldbus and Profibus devices over the past 10 years or more. Just copy and paste EDDL files — there is no need to learn new software installation procedures or licence key skills. Adopting the new EDDL enhancements is easy, as procedures remain the same and the interface cards and multiplexers remain the same. Only a one-time upgrade of the system software is required, and this is done by the system manufacturer.

Investment protection

Plants will live with their systems for a long time. The enhancements to EDDL are built on the tried-and-tested traditional DD platform and incorporate new graphical elements — EDDL is a mature technology based on the DD heritage. Thousands of sites already use traditional DD, and EDDL enhancements are already proven in hundreds of sites. More and more devices are making full use of the enhanced infrastructure so the standard is playing out nicely for millions of installed devices and thousands of systems.

Because EDDL files are not software, it is not made obsolete by new versions of Windows over the long term, as required by NAMUR NE 105. EDDL is a solution for those who are in it for the long haul. Upgrading a system from traditional DD to enhanced EDDL adds value to the existing infrastructure and staves off obsolescence for several years.

*Jonas Berge is Director, PlantWeb Consulting, at Emerson Process Management.