Wednesday, March 31, 2010

Spring public review is underway

Several proposed new addenda to the BACnet (Standard 135) and the associated testing standard (135.1) are out for public review, March 26th through May 10th, at

These are:

Addendum 135-2008g: BACnet network security

Addendum 135-2008i: BACnet lighting control

Addendum 135-2008z: Miscellaneous changes

Addendum 135-2008ab: Adding more standard MS/TP baud rates

Addendum 135-2008ac: Clarifying (hopefully!) the use of Dates and Times
Addendum 135.1-2009e: Revising BACnet/IP tests

Addendum 135.1-2009f: A set of new and revised tests

Addendum 135.1-2009g: (Mislabeled -2007 on the website) A set of new and revised tests

Addendum 135.1-2009h: Change several tests

Thursday, March 25, 2010

BAC in the Saddle Again

...and glad to be here! It's not like the Smart Grid activities are ramping down (3 hours of teleconferences today), but I finally managed to get free for the BACnet Testing Labs working group teleconference this morning, and to start in on the revisions to the BACnet Elevator proposal.

As regards that proposal, the recent publication of Addendum 135-1008y, with its addition of a number of "simple value" objects, simplifies some aspects of the re-draft. I didn't have that as a given when I wrote the current draft.

Monday, March 22, 2010

Standard 135.1-2009 has been published

Just received an e-mail with Subject: line as shown. I mentioned this a few days ago.

Saturday, March 20, 2010

"Saving Energy and Money" talk at NFMT

Speaking at the NFMT 2010 conference this week was quite an experience. Looking at the hall beforehand was itself daunting (TWO screens with seating for over 300, estimating from the early-morning photo), and the room was nearly packed. And there was much interest -- a number of questions after I finished, and even more privately afterwards (perhaps fortunate that we were on an extended break so I could take them right there).

The interest in the topic of "how to save energy and money" (and I've seen very little in ideas outside what's already in the literature --standards, green building rating systems and guidelines-- I present) is higher than I've ever seen it.

Given my participation in multiple seats in the Smart Grid Architectural Committee, this is gratifying. IF we can change the various mechanisms and timings of energy grid loads, we can reduce the need for new power plants and new distribution system loads (and this goes all the way down to to your house with the demand & supply capabilities of electric vehicles -- they are NOT a neutral introduction to the grid!). But a more considered use of energy by commercial buildings will give us more breathing room.

And some of what can be done is achievable in existing buildings with existing infrastructure.

I will be delivering a revised version of this talk at Light+Building in Frankfurt Germany next month. It will be interesting to hear their feedback.

Friday, March 19, 2010

Revising the testing standard

A set of e-mail exchanges between ASHRAE and the current BACnet chair, Dave Robin, on wich I cc'ed, tipped me off to the fact that a new version of the BACnet testing standard, ASHRAE Standard 135.1-2009, is about to go to publication.

There isn't really a llot to say about 135.1-2009 except that it has incorporated a set of miscellaneous changes (one or two which may have been my proposed changed), things such as:

- Load Control object tests

- Testing new and required alarm services error returns

- A fix to acknowledging offnormal alarms

- Conditionally omitting some test provisions

- Changes to Group object functionality tests, and

- Labeling conditionally writable properties in the EPICS

It also updates references to the clauses in the BACnet standard from the 2004 version to the 2008 (ANSI/ASHRAE Standard 135-2008), per the BACnet committee's goal of publishing updated versions of the testing standard the year after the BACnet standard is itself updated.

A small list and pretty dry stuff, especially when compared to the wild and wooly BACnet standard itself, but it's work somebody has to do. And there are some of us* in the BTL-WG doing it: a lot more changes are in the pipeline.

* Though lately I've not been able to do much. Smart Grid teleconferences are conflicting with this groups -- though yesterday when a lack of conflict meant I was all ready to re-engage the BTL-WG... that teleconference was canceled due to technical problems!

Tuesday, March 16, 2010

Live from the SGIP meeting

The second face-to-face meeting of the SGIP (Smart Grid Interoperability Panel, formed under NIST per the Energy Independence and Security Act) plenary meeting is now underway in Chantilly, VA. Up to 562 member organizations involved now, with 1498 individual members.

Thursday, March 11, 2010

Contrasting implementers

It was an interesting week for BACnet questions. The first e-mail came from a former sales colleague asking about Multi-state objects (MSOs). He saw a display of somebody's MSO object showing a State_Text property as an array with elements 1 to 4, but with state values from 0 to 3. This didn't look right to him, and I confirmed that. In fact the standard itself says, "The Present_Value property shall always have a value greater than zero." (12.20.4, Present_Value)

Perhaps the language here is too vague if an implementer made this mistake (and it has happened before.) In this case, though, I know nothing about the software displaying this so I can only hope that maybe somebody had mis-programmed the display.

But the other e-mail painted quite a contrast. It noted that the author had difficulty understanding " DONE_WITH_TOKEN " in the MS/TP Master node machine, to wit:

At Page 89, the "SendToken" item, "If FrameCount is greater than or equal to Nmax_info_frames and TokenCount is less than Npoll-1 and SoleMaster is FALSE, or if NS is equal to (TS+1) modulo (Nmax_master +1)," , the last part, which I put underline, is difficult to understand for me. The expression confuses me logically. The "or" is refer to Which condition/conditions ?

Here the implementer is really trying to be careful. And I admit I have not looked at this state machine in years, so it took me a while to work it out. Finally I determined it was correct -- everything before the comma is one condition, what follows is another. (The test is to determine whether or not to send a Poll For Master frame -- if the Token hasn't been around Npoll times since the last poll OR if there is a Master node with a MAC address one higher than this node, don't poll.)

IMHO it's always better to ask if you're not certain; it's better than putting erroneous implementations in the field.

AND always have the device tested by a BACnet testing lab!

Tuesday, March 9, 2010

Missing meetings

It's becoming too much a regular thing now. I receive an e-mail from OS-WG convener (and BACnet committee secretary) Bernhard Isler announcing the week's teleconference of the Alarm Summit (developing BACnet alarm extensions), and I send my regrets for missing yet another one.

This week it was for two: tomorrow we wrap up a Smart-Grid-related meeting of the Energy Information Standards Alliance's buildings group in Phoenix, and next week because I'll be speaking at the NFMT conference in Baltimore (missing the second day of NIST's Smart Grid Interoperability Panel meeting nearby).

But if nothing else comes up I can find out on the 24th what kind of "trouble" the Summit is getting into.

Friday, March 5, 2010


It's one of those things you know, maybe even think about from time to time, but it doesn't quite become real until it happens...

In this case it's being dependent upon the work laptop. As I learned a day and a half ago when mine was stolen in one of Seattle's recently numerous "smash & grab" incidents -- somebody saw a backpack on the floor of my car (it's a mini SUV with no trunk), smashed a window and grabbed it. With my work laptop inside. (The drive is encrypted, not that there were any corporate or personal secrets on it.)

Immediately my work life was pretty much shut down. No e-mail, no meeting reminders, no teleconferences. At least I had backed the machine up just days earlier so I lost little in terms of work product. A co-worker found a spare laptop so I am back up and running again. Now I have to navigate the corporate maze of getting a replacement.

But I was able to use the day yesterday to move to a new office, the new home of The BAC Cave.

Monday, March 1, 2010

THAT's why it's so difficult...

"A picture is worth a thousand words" -- how true that is sometimes. Trying to explain to folks at Alerton my involvement in the BACnet world was extremely frustrating because they couldn't put all the various pieces together. Eventually I just drew a diagram of the various BACnet-related organizations and committees, who talks to whom, and with my various roles (other than member or participant) spelled out, and the bubbles colored where I was an actrive participant. I pulled that out today and updated it -- there are new organizations such as BIG-China that have appeared since the last revision, and a few subcommittees or working groups that have wrapped up and gone home. The end result looks something like this (sorry the text is not legible at this reduction), based around ISO/TC205 (yellow), the BACnet committee (green), BACnet International (light blue) and BIG-EU (purple/magenta).

Recently I had a similar difficulty in just describing how I am connected to the Smart Grid efforts and the NIST Smart Grid Interoperability panel, and part of it was that even I didn't have a good image of how the various pieces fit together.

So I killed some time on the plane last week by researching the connections and sketching maps. My American supervisor said Friday he thought this might be a help to him, so I went ahead and drew it up -- again with the committees or organizations I work with in color. Once that was done, it was clear why it was hard to explain verbally. (For this posting I highlighted my name in yellow; some other colleagues are named in this diagram, and I see I missed one of their connections -- sorry, Tariq.)