A Device Description ("DD") is a formal description of the data and operating procedures for a field device, including commands, menus and display formats. It describes exactly what you can do to that particular device by HART communication. It is written as plain text, but is converted into a coded ("tokenised") form for use, for greater efficiency.
For more details visit: https://fieldcommgroup.org/technologies/hart
If you have any questions, please contact Technical Services or your local Brooks Instrument representative for assistance.