I read with interest the article by Peter Ebert on field diagnostics. To me and to many of us that deal with fieldbus technology on a regular basis, the diagnostics issue is really an information management problem that can be solved with the technology we have today, and there are key differences in how Foundation fieldbus handles diagnostics versus HART and other protocols.
Let’s start with NAMUR NE 107, which the Fieldbus Foundation has incorporated into our specification. NE 107 diagnostics have been part of our specification since 2010. Our Field Diagnostics specification was developed in close collaboration with NAMUR [a German process industry user organization]. Many of the requirements outlined in the NAMUR recommendations, such as support of alarms, were already included in the specification.
In fact, all new devices that will be registered from this point on with Version 6 of our Interoperability Test Kit (ITK) must support NAMUR NE 107 graphics and diagnostic management capabilities. All of our host systems tested through our Host Profile Testing and Registration program must also conform—that’s especially applicable to our integrated DCS hosts. We are currently the only organization with this mandatory requirement for NAMUR NE 107 support for testing and registration of devices and hosts.
NAMUR NE 107 is extremely valuable because it not only creates standard symbols and terms for reporting diagnostic conditions, it makes it a lot easier to classify diagnostics in terms of severity and root cause (i.e. is it a process problem? A sensor problem? An electronics problem?)
Yes, both HART and Foundation fieldbus and lots of other protocols offer diagnostic information. However, when you go completely digital as you do with Foundation fieldbus, the volume and type of diagnostics that are available to you increase exponentially, as does the bandwidth to report these diagnostic conditions (all-digital, so you can transmit multiple process variables and diagnostic conditions across the network).
The Foundation publish/subscribe architecture also means that diagnostic information is continuously pushed to the people that need it, when they need it, with no delay and no requirement for polling devices. All of a sudden you find yourself able to access thousands of diagnostic parameters at a time from many different devices across your fieldbus network. It’s like seeing television in high definition for the first time, and it goes way beyond the ability to detect a plugged impulse line.
You need a common sense way to manage the information you are getting so that it is actionable, and people only get the right information to the right people at the right time. That’s the real beauty of NAMUR NE 107 and why our end user clients decided it was time to make these recommendations part of the Foundation fieldbus specification. Because we are an open standard guided by our end user council, we can make additions and improvements to the specification as they are required.
The all-digital nature of our diagnostic capabilities also allow users take the whole diagnostics platform up a level, by looking at interrelationships between diagnostic conditions on different devices across the unit or the plant to create diagnostic profiles of the process itself and even plant equipment. This takes diagnostics into a whole new dimension, where it becomes part of your overall plant optimization strategy.
I would be happy to write more about this topic, as I think it is one of the most misunderstood topics facing our industry today.
Larry O’Brien, [email protected], is global marketing manager with Fieldbus Foundation
