in reply to: HART Interoperability posted by balaji on 15 July 2007 at 07:39:24.
I see interoperabilty as meaning two things:
1. Components from different manufacturers should work well together. Users can choose the best supplier for each part of a system, without any lock-in.
2. Devices to a newer version of the protocol should work well with devices to older versions, and vice versa.
HART offers both these:
1. Standard Universal and Common-practice commands make a start for basic functions; Device Descriptions make a further advance by allowing a DD-enabled host to operate fully with any new device; and (eventually) Family Device specifications will allow easy exchange of devices sharing a defined set of configuration parameters.
2. The rules for HART protocol enhancements and device enhancements are very strict, and ensure this since revision 5. Extra features (new commands, more data) may be added, never taken away. New features not understood are simply ignored by older devices.
You might also like to look at the Powerpoint file http://eddl.org/files/HART-PR-files/HART-NAMUR-files/hart-ddl.1.ppt