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175RE: [BACnetLighting] Re: Meeting in Louisville, Kentucky

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  • David Ritter
    Jun 9, 2009
    • 0 Attachment

      Hi Steve & all,

       

      Thanks for all the responses to my previous email.

       

      Let me give a bit more background regarding the sunrise/sunset issue. As Steve has pointed out there was an changed proposed to the BACnet schedule object in Addendum w called “Add reference times for scheduling”. There were public review comments on this part of the addendum which pointed out a few flaws with it and consequentially it was decided to remove it from the addendum when it goes out for a second public review (sometime this fall). I was tasked with coming up with new change proposal for adding sunrise/sunset to the BACnet schedule.

       

      In internal meetings here at Delta last week this issue was discussed and it became obvious that simply adding sunrise/sunset to the schedule may cause problems and unintended results. The problems are realized in high north (and lower south locations) when sunrise and sunset can flip as you approach summer solstice. For example, today in Fairbanks Alaska the sun sets at 3:11 AM but rises at 12:29 AM. If you were to set up a BACnet schedule to control the parking lot lights to come on at sunset and turn off at midnight, this would work fine in Fairbanks until May 29th. On May 30th  Fairbanks does not have a sunset and on May 31st  sunset would occur at 12:02 AM so you would effectively leave the parking lot lights on for almost the whole day. An analogous situation occurs when you approach the winter solstice. It can be argued that adding sunrise and sunset, without explicit restrictions to avoid these complications, would be a bad thing.

       

      As we were discussing how to solve this problem the question came up as to who would use this feature? Our lighting people indicated that they would rarely do a sunrise/sunset application using schedules but would use photocells. Paul’s email from Friday would seem to back this up.

       

      So the question is do we really need sunrise and sunset infused into the BACnet schedule or are there better ways to handle this?

       

      Thanks

       

      David Ritter M.Sc.

      Delta Controls Inc.

      17850 56th Ave

      Surrey, BC

      V3S 1C7

      604.574-8492 (direct)

      604.574.9444 (office)

      604.837-1330 (cellphone)

       

      From: BACnetLighting@yahoogroups.com [mailto:BACnetLighting@yahoogroups.com] On Behalf Of Steve Karg
      Sent: Monday, June 08, 2009 4:51 PM
      To: BACnetLighting@yahoogroups.com
      Subject: [BACnetLighting] Re: Meeting in Louisville, Kentucky

       




      Hi David,

      I will add the item to the agenda.

      Is not the Addendum that just went out for public review with
      Primitive Value objects and the Time reference not sufficient for
      Sunrise and Sunset?

      Best Regards,

      Steve

      On 6/4/09, David Ritter <dritter@...> wrote:

      > Hi Steve & all,
      >
      >
      >
      > I don't know if we will have time for this agenda item in Louisville but
      > could we have a brief discussion regarding adding sunrise and sunset to
      > the schedule object? Specifically, I would like to know how people are
      > currently using sunrise and sunset in their implementations and how they
      > would expect it to work within a BACnet schedule.
      >
      >
      >
      > See you in Louisville.
      >
      >
      >
      > David Ritter M.Sc.
      >
      > Delta Controls Inc.
      >
      > 17850 56th Ave
      >
      > Surrey, BC
      >
      > V3S 1C7
      >
      > 604.574-8492 (direct)
      >
      > 604.574.9444 (office)
      >
      > 604.837-1330 (cellphone)
      >
      >
      >
      > From: BACnetLighting@yahoogroups.com
      > [mailto:BACnetLighting@yahoogroups.com]
      On Behalf Of Steve Karg
      > Sent: Friday, May 29, 2009 10:10 AM
      > To: BACnet Lighting Working Group
      > Subject: [BACnetLighting] Meeting in Louisville, Kentucky
      >
      >
      >
      >
      >
      >
      >
      >
      > Hello BACnet Lighting Working Group!
      >
      > We are scheduled to meet on Thursday, June 18, 2009, from 8am to 5pm,
      > in the Morrow Room of the Galt House in Louisville, Kentucky.
      >
      href="http://www.galthouse.com/uploadedFiles/Meetings_and_Events/SUITE_Tower_3">http://www.galthouse.com/uploadedFiles/Meetings_and_Events/SUITE_Tower_3
      > rdFloor_Skywalk_Level.pdf
      >
      > All meeting rooms are in the the conference hotel:
      > The Galt House Hotel and Suites
      > 140 North Fourth St
      > Louisville, KY 40202.
      >
      > As usual, the plenary meetings for SSPC-135 BACnet will be on Saturday
      > and Monday (June 20 and June 22). Other BACnet working group meetings
      > will be held on Thursday, Friday, and Sunday (June 18, June 19, and
      > June 21).
      >
      > LA-WG agenda items:
      >
      > 1. Review and respond to the SSPC-135-2008 Addendum i PPR3 Comments.
      >
      > 2. Discuss proposed Addendum H clause H.X Using BACnet with DALI
      > (RLH-001)
      >
      > Please post any additional Lighting Application working group agenda
      > items to this list.
      >
      > Best Regards,
      >
      > Steve Karg
      > The Watt Stopper / Legrand
      > --
      > http://steve.kargs.net/
      >
      >
      >
      >

      --
      Sent from my mobile device

      http://steve.kargs.net/

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