RE: [BACnetLighting] Emailing: DHR-021-05 [1 Attachment]
As I am unable to attend the Denver meeting, here are some comments regarding this revision.
First of all, the changes look OK to me based on what your tasks
were from the previous meeting.
re: DR1 comment
I don’t see why Change_Of_State_Count could not be used as long as it retains
the language of 12.X.18.
re: DR2 comment
You’re correct that the language could be more consistent with BO object.
However as an historical note the BO object has long been flawed in this
respect because it fails to base the state change on ACTUAL changes
by observing feedback value instead of PV. If we want a reflection of
runtime and strike counts that are meaningful it should be using feedback
in all cases. If there is no feedback, then it’s a local matter and you could
implement it literally as the BO object says. If there is feedback but you use
the PV instead, then in cases of lamp failure one would accumulate run hours
even though the lamp isn’t running. So depending on how quickly you get
around to noticing that the lamp has failed, your statistics are going to be skewed
by that delay. Since the purpose of gathering run hours is at least partially to
gauge things like lamp life, this is at cross purposes when PV is used instead.
IMHO we should leave the language as-is and try to introduce similar language
into the BO object!
re: DR3 comment
Strike_Count (or Change_Of_State_Count) should be required writable so that
it can be cleared by writing zero. This should be coupled to Elapsed_Active_Time
as in BO object.
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[Attachment(s) from David Ritter included below]
Here is an updated version of DHR-021 (Binary Lighting object type) for discussion at the LA-WG meeting in Denver next week. There are a few things to discuss before this document gets moved up to the SSPC again.
Hope to see you in Denver,