I’m going to Disneyworld!
January 21, 2010 – 12:21 pm
I’m currently in Orlando, Florida. Not to visit the mouse, but to attend BACnet meetings as part of the 2010 Winter AHR Expo. BACnet is an ASHRAE standard and as such, the SSPC and the various working groups hold their meetings directly prior to the AHR show.
The working groups usually meet for 3 days and the main SSPC meets for 2 days.
Today was the first day of the meetings. I decided to attend the BTL-WG meeting and David attended the LA-WG (lighting application working group). This made sense because I’ve been active with the BTL-WG for a lot of years. Also, David has been spearheading a lot of the effort in the LA-WG along with Steve Karg.
BTL stands for BACnet Test Labs, which is a part of BACnet International. The test lab is currently managed by Duffy O’Craven, who has been a fellow BACneteer for about 10 years, which is also about how long I’ve been working with BACnet – so Duffy and I have definitely chewed some of the same dirt.
The BTL-WG is near and dear to my heart, because that’s the group I originally started working with when I first joined the BACnet community. These days, the working group meetings are pretty civil, but I remember a time when that was not the case!!! Those days still bring a smile to my face.
We’re currently on our lunch break, but we were able to accomplish quite a bit this morning and we certainly jumped in with both feet. We discussed a few clarification requests. All of these documents have yielded interesting conversations. The most intense of which has been a conversation of the functionality checklist for the new Trend Log Multiple object. The problem with (what I consider) “complex” objects is that some of them allow the use of ANY datatype as a value. The ANY datatype unfortunately allows all of the primitive BACnet types ALONG with all of the complex types as values. Most of the time, though, only a small set of the data types really make sense for a particular object, though. For instance, in the case of trending, how often will you trend an object-identifer whose value will (well, should) never change. So, in the checklist we were discussing how to list the optional datatypes supported for the trend log multiple. Limiting the datatypes supported is a good thing for interoperability, IMHO. It’s because a client device, hopefully, will know what to expect when requesting data from a server device.
A lot of times, during these conversations, I try to visualize the functional use case for the particular thing we’re discussing. Determining use cases for these things is an acquired skill and sometimes it’s quite difficult to keep up with the conversations if these use cases aren’t on the tip of your tongue. It takes a lot of processing power to listen and digest the information being passed around at a rapid fire pace and it can be very exhausting. It’s a good thing there’s a steady supply of coffee available!
I’ve also taken on a work item for one of the MS/TP tests, which deals with the max-info-frames setting in a device and what can be expected to be sent from an MS/TP device based on the value of this property.
Tomorrow is OS-WG, AP-WG, XML-WG, and the TI-WG.
Of particular importance to me are the IT-WG, IP-WG, and SG-WG meetings on Sunday since the IPv6 work we’ll be doing in the IP-WG will likely be heavily discussed and debated ad nauseum.
Coffee helps me clear the fog. If you've found any of the posts on this blog helpful, I could always use more coffee.