Attention end users! This one is for you. You get the kinds of products that you are willing to insist on.
One of the big problems in convergence between the international wireless field device standard, IEC62591-WirelessHART and the as yet unapproved ISA100.11a-2011 proposed standard is the fact that ISA100 does not mandate a basic Application Profile that all vendors' products must contain. Essentially, this means that there is no check or balance that makes interoperability and interchangeability automatic.
I've just received the responses to the comments on the most recent ballot to approve ISA100.11a.
Once again, the members of the Working Group 3 editorial team are relying on the ability of the Wireless Compliance Institute (a private, wholly owned subsidiary of ISA) to ensure that the standard, even though it is missing some essential parts, somehow enforces interoperability and interchangeablity, and that it will continue to ensure those things into the future--instead of writing those very important to end users issues directly into the standard. Maybe that will work, but I don't think so.
Here's one of the comments: (regarding the provisions for channel hopping in the proposed standard) "This is an example of ISA100.11a introducing a function that is incompatible with convergence [with IEC62591- ed.] that has no justification in the system requirements or use cases."
The editorial team responded, "In the editors' view, configurable hopping patterns are an essential part of the ISA100.11a design, and, in the editors' view, lack of configurability on this point is a design error in IEC 62591 that should not be carried forward in a converged solution." Comment rejected.
So there.
No convergence for you, end users.
I find the timing of this resolution of comments report interesting. Next week, in Orlando, the ISA100.12 committee is meeting to hear proposals for convergence between the two standards. Clearly, the WG3's answer is to adopt ISA100.11a instead of WirelessHART and let the end users who have already bought more than $100 million worth of those devices go hang.
How does that feel, end users?
I've been saying for several years now that the obvious solution to convergence is to simply adopt IEC 62591 as the ISA100.11a standard and be done with it. There's even precedent in ISA standards work for doing this. the IEC safety standards were adopted wholesale as the revised ISA-84 standard.
The fact that there is no default application profile, and the fact that network channel hopping can be configured to make other devices incompatible with ISA100 would lead any end user to conclude that buying an ISA100 wireless product, even if it is certified by the Wireless Compliance Institute, does not guarantee that there will be no compatibility issues going forward. Even if it works now, it may not work in the future.
So, end user, here's your dilemma. Should you recommend a standard with no firm guarantee that it enforces interchangeability and interoperability? Or should you go with a standard that does guarantee interchangeability, and interoperability because backward compatibility is designed into the standard?
Would you bet your career on the decision you make?
I am getting sick and tired of the ISA and the vendor community not paying attention to the anguished cries of the end user community for a single standard. I guess they think you are all going to roll over for whatever they want to sell you. And in fairness, there's a history of them being right about that.
So, end users, either stand up and demand a converged single wireless field device standard, or be happy when you get stuff that isn't what you thought it might be. It is YOUR move.
