Seems to me that a big issue with interoperability for devices and systems is that EDDLs need to be updated to all handhelds and stations. It looks like EDDLs have come a long ways, but they have not made the simple jump into being stored in the actual devices on board memory. During an initiation phase of a device, the master should look in a specific memory location on the device and be capable of extracting it from the actual device. This capability was discussed in something I read awhile back, but I can't find anything related now. Anyone have any knowledge on the progress of this?

 

As long ago as the original 1990's when the ISA SP50 standards committee was writing the User Layer that became the basis for Foundation Fieldbus function blocks, we identified "attributes" that became Device Descriptions. We assumed that these would be read-only data items and always stored on the device. Until the recent Foundation project, I never knew that the instrument builders actually stored them on the DCS. I guess it was a cost issue then, but it should not be now. I like this solution, and am pleased that you made your observations.

Thank you.

 

Isn't the EDDL the 1-2Mb file, a DTM or DD file, that defines the objects in a specific model that is loaded into the software and used to communicate with that model instrument? Or is it some other file? Maybe it's not a HART file ? ?

If it is the HART DD file, and assuming the mfg saved the DD in the field instrument, would it make any sense?

Who wants to wait 15 minutes to load a 1Mb file from a HART transmitter onto a handheld at 1200 baud?

Is Hart even smart enough to retry and get those missing bytes that got noise savaged? Or would it wait to the end and pop up a message like, "Sorry, COM error. Try again".

Maybe a fieldbus like FF (at 38K or whatever the precise number baud rate is) could make a file transfer in something less than a morning but HART doesn't seem to have wherewithal.

 

Not available yet. FOUNDATION fieldbus does support the capability to store the DD (EDDL) file in the device and upload it to the system. A lot of people are asking for vendors to implement this. It would be really neat.

I'm sure it will come in product someday. It would give device vendors
greater freedom to release new features more frequently

Cheers,
Jonas