EDDL and FDT

[mohantg]

So much of discussions are on about EDDL and FDT/DTM.While buying fieldbus transmitters for a refinery or any oil and gas industry,can anyone suggest,
1.which one is the better option?
2.Do all the fieldbus transmitter and fieldbus positioner vendors support both the technologies?

[rezabejd]

It's hard to say which is "better" at the moment. There isn't a lot of product actually released.

EDDL has some advantages; it is a joint effort by FF, Profibus, and HART, it is a compact text-based file, so it's platform independent (FDT/DTM files are potentially multi-megabyte executable (.exe) files & needs a Windows OS).

With FDT/DTM, you are dealing with some large chunks of software, from two potentially different sources. If a task fails - say running valve diagnostics - whose problem is it? DCS or device?

You may find this article (http://www.controlglobal.com/articles/2006/110.html) interetsting; it's from last year but I think many of the points are still relevant.

[spragujl]

I agree with John - it's hard to say which which is better. It'll probably depend on the application, e.g. less complex instrument (P, DP, T xmtr) best with EDDL, a more complex device (positioners, analyzers, multivariable xmtrs) maybe best with FDT-DTM. My personal view is that any instrument that requires OEM software to setup, diagnose or maintain, needs to have that software available on/via the Host DCS (e.g. requires FDT-DTM).

But the good news is it appears that all the major DCS suppliers (with one notable exception) are supporting both EDDL and FDT-DTM. So, users can choose. I have read that WIB (Intl Instrument End Users Assn - NL) will be doing some comparative funtionality testing between EDDL and FDT-DTM in the next few months. It'll be interesting to see how the test is designed and results.

[jberge]

Since ENHANCED-EDDL is already available and has become an international standard (IEC 61804-3) all should take a close look at it. I personally feel that this new Enhanced EDDL has some very interesting characteristics (some new, some inherited from EDDL):
• It is robust since it is interpreted text (like a web page) rather than executable software that could potentially crash
• It is secure since it is interpreted text rather than executable software that could include malware
• It is an international standard
• It also enables software to make information externally accessible, not just show it on the screen. This is what OPC-UA is doing
• It is a single universal solution that works for device management software, handheld communicators, embedded web-servers, and control system configuration tools as well as being web-friendly.
• It provides investment protection as EDDL files don't go obsolete when operating systems change since it is interpreted text rather than executable software, with track record since 1992
• You get consistent display of devices since it works for not only PROFIBUS and HART, but also Ff devices - simple as well as advanced.
• You avoid version conflicts because there is one unique EDDL file for every version of every device, and it is interpreted text rather than executable software - important since they come from very many suppliers where all permutaitons cannot be tested together.
• The cross-platform compatibility provides peace of mind for operating system and software upgrades and patches since it is interpreted text rather than executable software
• Integration and removal is easy since files are simply copied onto disk without need to install software, have high privilege access rights, or uninstall old versions all which may or may not be successful
• There is no licensing required since it is interpreted text rather than executable software
• It provides full support of device functionality including for positioners and drives etc. with all graphics and visuals those require (this was a weak point of old EDDL)
• The EDDL is tested along with the device

It combines the well-known benefits of EDDL we have enjoyed for 15 years plus dazzling visual presentation of graphical data.

Go to this site and download the brochure:
http://www.fieldbus.org/eddl

Jonas