Thursday, September 30, 2010

Upcoming Plugfests

Heads' up: Deadlines for the B.I. autumn plugfest November 16-18 in Atlanta are a couple weeks away.
BIG-EU's spring plugfest is tentatively set for May 9-13, 2011, possibly in either Vienna, Austria or Dortmund, Germany. More as it develops.

Hope to see you there.

Update: Looks like it will be in Saarbrücken.

Facility Decision's Leaders of the Pack awards

Well, this should be a fun event! I received an e-mail announcing Facility Decisions' Monday evening reception AND BACnet International's Leaders of the Pack award ceremony Tuesday (Oct. 5, Exhibit Hall, 3:30 PM). The awards and descriptions are as follows (click on the image for larger version):

Oh darn. I vaguely remember receiving an e-mail about nominations, but it came at a time when my Inbox was overflowing daily with Smart Grid e-mails. I wonder if I can find it in order to nominate David Fisher for the Rottweiler Award.

Wednesday, September 29, 2010

Addendum on the Luce(rne)

Shortly after the exchanges noted in the preceding posting, I received the folloowing e-mail with a photo from our dinner cruise last week:

Hi Bill,

have to say that no addendum gets lost because of you.... but what the heck, what addendum were you shooting?


Well, Teemu, I'd like to say it was the latest effort to "socialize" new proposed changes to the BACnet standard, something like this proposed Addendum 135-2008ag:

But I won't.

The Hazard of Change

To borrow a term I hear a lot in the Smart Grid world, it seems those of us on the BACnet Committee aren't doing enough to "socialize" changes, mostly additions, to the standard. This became clear today with an exchange today on the BACNET-L email list.

John Arwine (just a short ways down the road from here) noted that he was working witha new BACnet controller, one of the first BACnet devices from its manufacturer. The documentation for the device identified it as having Analog Variables, Digital Variables, and Integer Variables. He hadn't heard of the last and asked the list whether this was a defined BACnet object type.

I responded:

Yes. If you look at Addendum 135-2008w (, you will find:
12.G Integer Value Object Type
12.H Positive Integer Value Object Type

This was published early this year.

And it was. It didn't take me long to dig out a copy of the addendum because I knew what I was looking for, even though I no longer keep all the BACnet addenda letters and their contents mentally correlated.

With 33 addenda, Addendum a currently through through ag, and many of them coompilations of miscellaneous unrelated changes, it gets difficult -- especially when I'm putting in a LOT more time these days on work on the Smart Grid than on BACnet.

But at least I knew where to turn and what to look for. The description of the contents of Addendum w is unusually terse, both in the addendum and on the web page, saying only "135-2008w-1. Add more primitive value objects, p. 2." This could be easy to miss if one were looking for "Integer Variables."

So we're making these additions, but not getting the information out to our users as well as we should. This is not a good thing.


Committee chair Dave Robin had a good response too (sparing me the necessityof a followup, thank you Dave!), noting that the terminology being used by the manufacturer was nonstandard. For many BACnet oldtimers the use of "unofficial" terminology provides a warning that something might be misinterpreted.

Quite possible in this case where a "Integer Variable" might be a new Integer Value or Positive Integer Value object, or it could be a Multi-state Value object.

So now John has a new task, to find out which of these object is intended -- if it's not a proprietary object!

Tuesday, September 28, 2010

How to read large BACnet Arrays

There's some very active discussion going on in the BACNET-L mailing list about how to read arrays that are too large to fit in a single APDU when segmentation isn't supported. The solution, as Frank Schubert pointed out this morning, is to be found in the BTL Implementation Guidelines (for download), to wit:

3.4 Be prepared to read the Object_List array element by element

Some small devices that do not support segmentation have Object_List properties that are too large to transmit unsegmented. If a device needs to read another’s Object_List property, be prepared to read it array element by array element.

This could be a little slow for clients reading the Object_List of devices with thousands of aobjects, however. There was discussion of a proposal before the committee to use ReadRange to read the array in "chunks", rather a bit less tedious, but a little quick research revealed that the committee tabled that proposal (vote: 1-8-4) in the spring meeting last May.

But the initial question that started this discussion posed a thornier problem: a physical access control device with hundreds of thousands of objects. Even segmentation will not help here because the segmentation counter would have to wrap. (Perhaps someone can research the language change that would allow that to occur?)

Reading the Object_List of one of these devices, array element by array element, would take quite some time. Using ReadPropertyMultiple to read by "chunks" would seem to be the best available solution at this time. At least unless and until the tabled proposal is brought back up.

(Note to implementers of such large server devices: be sure you can locate the last element of the Object_List quickly -- I have seen implementations fail to respond to such read requests before the client timed out because the server's linear search algorithm took too long.)

Monday, September 27, 2010

Didn't get the memo

Back when I began this blog, Marketing thought it would be a good idea to add a little bit of "social networking" along with it and suggested I sign up on Twitter (and, because the corporate firewall blocked Twitter), despite my protestations that "Swans don't tweet!"

Often when I posted on this blog, particularly for technical matters, I would sent out a (co)tweet right away -- the Marketing folks loved it.

But no more. Now the corporate firewall also blocks CoTweet. I wonder how long until Hmmmm hm hmmmmm meets the same fate; I guess IT didn't get the memo that some of this activity is corporately sanctioned. Or maybe it isn't official enough.

Oops: Turns out IT didn't do a thing. Some(?) of the firewall is "externally" managed and they were the ones to re-brand CoTweet. One of our IT folks checked the log for this month -- two accesses (one successful, one not) so we don't have a usage problem. And I am betting both accesses were mine. Now working with IT to get access.

Friday, September 24, 2010

Awright, who's the wag?!?

It's long been customary in the Alerton facility that if you're going to be away during regular work days you leave a Post-It note on your door stating, at a minimum, when you intend to return to the office. I usually leave more but because I had multiple destinations I just left a note saying, "Back 9/23."

When I returned I discovered that somebody had modified my note to read "Bac 9/23."

Very funny.

[For the non-native-English-speaking readers of this blog, the title is American slang for "All right, who's the joker?]"

Update: I suspected Johnny, but it turned out to be Dean.

Dinner Cruise

Looking up ship prefixes, there seem to be none for the famed Swiss navy -- or other Swiss vessels, for that matter. So the Titlis, named for a nearby mountain, will just have to be called by that name alone. (I believe that's Mount Titlis behind the ship in the photo.)

The surprise, when I saw the final agenda for the BIG-EU meeting in Lucerne this week, was that we would have a cruise with dinner Monday evening. This had been discussed for the group dinner, but when the Executive Board got the price we canceled it -- there was no way such an expense could be justified. So when I saw a cruise on the agenda I surmised that perhaps it was a cruise sans dinner or some such.

Nope. It was announced that day that three companies present in Switzerland had gotten together and jointly sponsored this most unforgettable cruise and dinner for the BIG-EU.

What else can I say but "Thank you!" to Saia, Sauter and Siemens. Switzerland was beautiful and pleasant enough already (I hope to visit again sometime), but this was the icing on the cake.

Tuesday, September 21, 2010

So long, Roger

Old-time North American BACneteers will remember Roger Braun (on the right), who had attended meetings at least from the kickoff of SSPC 135 in June, 1996. His last appearance in the minutes is in March, 2001, where it is noted what he would be resigning from the committee, his position as liaison to the European committee CEN/TC 247 to be taken up by René Quirighetti (recently retired).

He has done a yeoman's work for some time since as BIG-EU's Treasurer. But his employment has become such that he's now had to resign from BIG-EU and disappear completely from the BACnet world. But I hope that if/when BIG-EU returns to Switzerland, whether for meetings or plugfest, he'll put in an appearance.

So long and good luck, Roger.

Monday, September 20, 2010


The BIG-EU autumn meetings are underway here in Lucerne, Switzerland, starting with meetings of the technical and marketing working groups, followed by elections for the Executive and Advisory Boards, and on the second day a meeting of the joint Executive and Advisory boards.

The biggest topic on all the agendas is universal BACnet "certification" -- long a thorny topic due to differences between the systems in Europe and North America. But significant progress has been made. On the other hand, in meetings of the SGIP's Smart Grid Testing & Conformance Committee last week it appears that the North American certification scheme will soon change to become more like the European scheme.

Friday, September 17, 2010

BACnet Committee autumn meetings announced

Earlier this week BACnet committee chair Dave Robin announced the autumn meeting of the BACnet committee, to be held October 25-29 on the Georgia Tech campus in Atlanta, Georgia. As he notes, "This year we again have a block of rooms reserved at the adjoining Georgia Tech Conference Center Hotel, but room reservations should be made by September 24 to receive the greatly reduced rate."

The meeting schedule of the working groups and the plenary follows. (The working groups and their functions are defined here.) As always, the meetings are open to all interested parties. I expect an official announcement to appear on the BACnet website shortly -- though if you want details before then contact me.

Thursday, September 16, 2010

The Fortune Cookie

After lunch during the SGIP meeting today I had dessert -- something rare for me. Pineapple upside-down cake and a fortune cookie? Okay...

The fortune within fit so perfectly I had to add it to my badge (at the bottom):

Smart Grid PAP17 working group kickoff

(Click on the picture to enlarge it.)

Today the SGIP's PAP17 ("Priority Action Plan 17") working group kicks off with its first meeting.

Subtitled "Facility Smart Grid Information Standard" (in this context "facility" means "building" and primarily refers to commercial and industrial building consumers of electricity), it will operate in parallel and in part as a feeder to the ASHRAE/NEMA SPC 201 committee, named "Facility Smart Grid Information Model," which had its kickoff meeting 2-1/2 weeks ago.

All of this is part of the high-speed effort to develop the Smart Grid, our part being the consumer end of the Grid. There are many other groups representing the producers, distributors, transmission line operators and a surprisingly large number of other parties involved in the generation and delivery of electricity. There's a diagram floating around somewhere I will add when I find it.

Found it. (Click to enlarge.) Please note that this diagram is a simplification of the real picture. For example, the "consumer" is not only residential as shown here, but includes commercial and industrial buildings.

Tuesday, September 14, 2010

Smart Grid meetings begin

I'm in St. Louis MO for the autumn meeting this week of NIST's Smart Grid Interoperability Panel (SGIP), complete with a sea of working group acronym soup including
PAPs ("Priority Action Plans" -- things needing to done soonest; I'm on 9, 10 & 17)
DEWGs ("Domain Expert Working Groups"; B2G or "Building to Grid")

You can see the agenda here. We are currently in the initial plenary, where we're getting updates about the progress of the SGIP -- now with 1700 members! But the work is also becoming more international, working with other countries; the goal being to have one Smart Grid (system) worldwide.

Autumn BACnet Public Review is open

In all the travel preparations (final prep for this and next week's travels, booking eary October trips plus travel requests for two others late October), I nearly forgot that on Friday ASHRAE began the autumn public review of a LOT of material for the BACnet standard (135-2008) and its testing standard (135.1-2009).

There is a lot of material to be reviewed, some of it in process for years, and more of it receiving many, many "committee-hours" (or rather, days!) outside of the regular comittee meetings in development. If you are a BACnet developer I strongly recommend you review these materials! And of course, submit comments if you have any. They are online as PDFs at

A quick rundown of what is in public review is as follows:
Addenda to Standard 135-2008:
Addendum ac: The (proper) Usage of Dates and Times
Addendum ad: Miscellaneous set of changes
Addendum ae: Tweaks to BACnet physical access control
Addendum af: MANY changes, especially major extensions to BACnet alarms
Addendum ag: Two miscellaneous changes

Addenda to Standard 135.1-2009:
Addendum e: BACnet/IP tests
Addendum f: Test Ack Notification timestamps
Addendum g: Add and change tests
Addendum h: Alarm tests
Addendum i: Improve/update/clarify/add tests

This public review is open from Sep 10th through Oct 25. I highly recommend reviewing these addenda and comment if you see anything (anyone can comment, by the way) -- if comments are not received they are automatically deemed to be acceptable to the public and made part of the standard; this is a final check on the work of the committee.

Wednesday, September 8, 2010

BACnet International Journal published!

Ever since I finally let go of all my electronics magazine subscriptionss (Electronic Design, EDN, EE Times, etc.) I've become a little lax in checking my mail slot at work because the mail volume has dropped considerably. But I checked it this morning and there was a package from BACnet International, containing a copy of the first issue of the new BACnet International Journal. Nice.
Take a look. (BTW, on p. 3 is a form where you can request a free subscription.)

Saturday, September 4, 2010


One of the interesting aspects of compiling the information for my Facility Decisions energy standards talk were the apparent inconsistencies in requirements and recommendations across the standards, guidelines and rating systems I reviewed (14 publications in all). For example, in LEED individual lighting controls are to be provided for 90% of building occupants; the exception is 50% in LEED for existing buildings -- though there's likely a good reason for that exception.

When it comes to turning off exterior lighting during the day, though, ASHRAE 90.1 says to use a combination of photosensor and time switch, or astronomical time switch. GBI 01-2010 says to use a time switch, photosensor or astronomical time switch. ASHRAE 189.1 doesn't care how you do it, just turn off the lights within 30 minutes after sunrise.

For CO2 sensors and demand-controlled ventilation (DCV), ASHRAE 90.1 says to use DCV for large, densely-occupied spaces. GBI 01 specifies regularly-occupied spaces (it defines "regularly-occupied") with occupancy variation >= 30%. LEED specifies it for densely-occupied spaces. And ASHRAE's Advanced Energy Design Guide for Small Offices says to use DCV in varying AND high-occupancy areas.

The list of inconsistencies goes on, including on alarms for ventilation system performance variation, the dampers to be used in air economizers, what water uses are to be metered or submetered, and so on.

Perhaps this isn't surprising. Some requirements are based on experience while some are speculative. Some of the differences are probably the result of independent publication development or disagreements with other requirements.

But nearly all of these documents are relatively new, having just been published within the last three years. I expect that with time and experience they will converge towards very similar recommendations or requirements.

Thursday, September 2, 2010

Deadline: Facility Decisions

Tomorrow is the deadline for submitting powerpoints for the upcoming Facility Decisions Conference*, October 5-6, 2010, in Las Vegas. Once again I'm racing to meet deadlines with my talk "Energy Standards & Energy Efficiency -- with BACnet." (So why on earth am I writing this now, except that I need a break?)

Although this is based on the talk I gave at the Building Performance Congress in Frankfurt last April there is new material to be added, revisions to be made, and a LOT of slide and text formatting to be done. I hope to finish it tomorrow so I don't have to beg to have the Labor Day holiday weekend to complete it.

(* The conference is free, by the way. I found last year's to be educational; why not consider attending?)