Bullish on BACnet
Editor's note: I first met Mike Newman of Cornell University back in 1997 at my first ASHRAE Winter Meeting when I serendipitously sat in on a member session on control strategies for campus environments. Not knowing who Mike was, I approached him afterward, as he seemed like someone who knew what he was talking about—and more precisely, could translate what, exactly, just transpired to t...
CSE: What’s new with BACnet?
Newman: Our efforts with XML and web services. There are really two things we’re concentrating on: 1) a generic definition of web services that can access any building’s automation sensors regardless of protocol, be it ModBus, BACnet, LON or somebody’s proprietary system, and 2) creating descriptions for how to build gateways for BACnet. We just completed our first review of the draft this past December and should have a second public review coming up within the year.
CSE: Why are you now pursuing your own XML standard apart from the efforts of oBIX (Open Building Information Exchange)?
Newman: We had been working on XML stuff for quite a while, but strictly in the context of BACnet.
Bushby: We also wanted something that could hold up to the ANSI and ISO process and, frankly, we felt oBIX didn’t have the standard’s arm to do that. At the same time, we were also concerned about the question of input. In other words, who was going to able to contribute? Finally, we also felt we did a big chunk of the development work and didn’t feel we were getting appropriate representation. But I think the bottom line was that we were afraid it might be a return to a failed architecture.
Swan: There’s also a difference between XML and web services, and there’s a separate committee studying XML in the context of procurement and whatnot. But as far as web services, it’s definitely something we should be pursuing. In fact, I just got out of a workshop on utilities integration, and one facility manager there described how all notification is still done over the phone. We need to figure out how we can automate this via the Internet and BAS, as the idea of web services is really to open the door to the next chapter of interoperability.
CSE: With ASHRAE going its own route on this matter, it raises a frequent criticism I hear of BACnet—that it’s too limited to one community and is really just the perspective of “a bunch of HVAC guys.”
Newman: Anyone who says that really doesn’t know ASHRAE. We’ve been reaching out to other disciplines since almost the beginning. In fact, we’ve tried working with the fire-protection community as far back as 1996 [when BACnet was officially adopted as an ANSI standard]. And even from the early days in the ’80s, at first, we did say, “Yes, this is for HVAC,” but we then added, “and for other building systems.” The first step was getting it accepted within ASHRAE, but throughout that whole process we always worked hard so as not to preclude others from eventual integration.
Bushby: We’ve also created ad-hoc committees with NEMA and set up a lighting-controls group with IESNA [the Illuminating Engineering Society of North America], and are presently working with SIA [Security Industry Assn.] on the security side.
Newman: I’d say we’ve been very active trying to work with others—not to tell them what to do, but how we can help or what we can learn.
CSE: So how do you overcome this perception?
Newman: We need to be more proactive and better at communicating the message that we’re not trying to dictate. To the contrary, we really want to learn.
Bushby: A lot of it also has to come from personal contact. We need to better identify the key players and the potential benefits for both sides. And we are doing so. For example, on the lighting side, we’re working right now with Lithonia, Leviton, Tri-Tec, Watt Stopper and Lutron, as well as with IESNA.
Newman: DALI [Digital Addressable Lighting Interface] is a good example. We’re presently working on how to better integrate it with BACnet because they go hand in glove. DALI has really taken off on the lighting side, but it has limited applications as it communicates hardly any data. But its low cost makes it great for ballasts and dimming. So we’re working on creating a BACnet object that will allow for better functionality at the controller level, but DALI will actually issue the commands to the ballasts.
CSE: On the subject of hot technology, there’s been a lot of buzz lately about wireless systems. What’s your take on the matter?
Newman: Putting on my facility manager’s hat, I’m skeptical. Wireless is certainly a great solution where things move around a lot, say, in office environments, but I question why I would want to do this where things are static. In many cases, I’d still have to run power for the devices, or I’d constantly have to change batteries, which is a maintenance nightmare.
Swan: Interference is a concern.
Bushby: Absolutely. One of the things I’ve heard that’s supposed to be a big advantage of wireless systems is that you’ll be able to add lots more sensors to a building. But like Bill, I have concerns about interference or more malicious attacks. Having more sensors is truly an advantage for better building control, but at the same time, it’s a weakness in that these sensors could be vulnerable to something known as “sleep deprivation” attacks. To stay “alive,” to Mike’s point, sensors need to be able to power down and go into sleep mode on a regular basis. But these sensors can be attacked when woken up by some sort of external signal. So that’s a big issue. Another well-hyped benefit is the alleged ability to easily relocate thermostats in a wireless environment. A concern I have, however, is what about the rest of the system? You can’t move the registers or vents or installed HVAC equipment.
Newman: I can definitely see the advantage of some kind of wireless system where you’re talking about improving a human-to-data exchange, say in a hospital. But in building automation, I think it’s more of a niche. And, certainly, a mechanical room is a horrible environment for wireless.
CSE: Back to the notion of reaching out, BACnet officially became an ISO standard two years ago. How has that affected the protocol’s adoption/exploration overseas?
Newman: It’s clear that the ISO approval has been a positive thing. It’s unbelievable how much it’s grown and expanded. In fact, we’re having trouble keeping up with who is using it. For example, I was at a party, and a gentleman wanted to introduce me to a group working on BACnet in Sweden, which was a complete surprise. Right now there are four official international interest groups, but as we’re finding out, there are lots of surprises.
Bushby: The Swedish news was also interesting because Scandinavia has always been a strong LON community. But even on the [AHR] show floor we saw some evidence of this in that TAC, which has its roots in both LON and Scandinavia, was exhibiting a new BACnet-compatible product.
Another thing I saw on the floor was that folks from ABB now offer a variable-frequency drive that’s tied to BACnet, and they said that’s been going gangbusters. So that’s encouraging. [Mitsubushi, also at AHR, announced it would soon release a BACnet-compatible drive].
Newman: At the same time, everything we’ve been hearing is really anecdotal. We don’t have any firm data. But still, it’s compelling in that it’s coming from lots of different places. Just the number of people showing up at the meetings; we’ve had delegates from Japan, China, Switzerland and Russia actually serving on the committee. It just keeps increasing.
Bushby: BACnet’s also doing well in Australia, especially out of the University of South Wales. There’s also a lot of interest in China, although the number of projects is still small. We’re also hopeful of making some inroads into the U.K. where the whole market for open protocols has soured.
Newman: The real telltale, in my opinion, is that we don’t hear about a lot of [BACnet interest] groups like these fading.
Other ’05 Winter Meeting Business
Following is a recap of other BACnet news that came out of the ASHRAE Winter meetings this past January in Orlando:
Addendum b contains new features related to advanced trend-logging capabilities and specialized alarm-handling capabilities important in Asian markets. It was recommended by the Standard 135 committee for a second public review following changes made as a result of comments received in a previous public review.
Also recommended for public review was Addendum a to 135.1-2003, Method of Test for Conformance to BACnet. This addendum defines new tests for features of BACnet that have been added since publication of the testing standard, as well as refinements based on experience from testing BACnet products.
The committee also reviewed comments received from the public review of BACnet/WS, the BACnet web services proposal. Responses to some of the comments were approved, and some of the suggestions were adopted by the committee.
The Utilities Interaction working group made progress toward standardizing the interfaces between energy utilities and buildings, approving two proposals, both with their roots in ASHRAE Research Project 1011-RP, Utility/Energy Management and Controls Systems Communication Protocol Requirements. One proposal provides a means for an organizational view of the objects in a BACnet device; the other defines a new load-control object.
Another proposal being discussed by the group makes use of the BACnet/WS proposal by using the web services as the standardized means by which the utilities would interact with buildings over the Internet.
Other issues being addressed by the committee include BACnet network security, common data models for CCTV and access control, and BACnet support for lighting-control applications.