Re: Understanding X10 Dims???

[nobody@xxxxxxxxxxxx (Dave Houston)]

The analysis holds up for triplets, quads, quints & sextuplets but there are
a few points that might be further refined.

Using the Kill-A-Watt & LM465 w/60W, I measure 145 microsteps to go from max
to min. This gives a 0.662% value for a microstep with the LM465. Other lamp
modules and switches may differ - the LM14A takes about 10 more microsteps
to go from max to min and it's min is far from full dim - my SmartHome lamp
modules do not respond to microsteps. The exact value for a microstep has
minimal impact as its effect is overwhelmed by that of the standard step.

The 96% figure is taken from various documentation - most from the same
experts who were off on the number of microsteps, off on the number of
standard dims and off on the explanation of how dims work. Someone more
able-bodied than am I with a Kill-A-Watt might be able to refine this figure
using a 300W load and measuring with and without the LM465 at max. I'm using
a small clamp-on gooseneck which is limited to 60W.

With the LM465, it takes 21 contiguous dims to go from max to min
brightness. Since the first one is a microstep, the value of the standard
steps is 4.767%. But this might actually be 20 plus some fraction which
would slightly increase the value of a standard step. A wattmeter with 1/10W
or better resolution could refine this.

ddl@danlan.*com (Dan Lanciani) wrote:

>In article <ZtidnVUsO8aJx2XfRVn-gQ@xxxxxxx>, ROBERT_GREEN1963@xxxxxxxxx (Robert Green) writes:
>| "Charles Sullivan" <cwsulliv@xxxxxxxxxxxx> wrote in message
>| news:pan.2005.08.08.21.58.32.976197@xxxxxxxxxxxxxxx
>| > Robert,
>| > Thanks for your response.  Yes, Dave's post is clear, but it
>| > doesn't answer my questions.
>| >
>| > I can direct the CM11A to send the same dims multiple times
>| > (with a few seconds delay in between) but the dims reported by
>| > another CM11A (looking at the actual byte reported, not converting
>| > to a percentage) vary by 1/210, occasionally 2/210. Why the
>| > variation?
>|
>| Sorry it didn't help.  I thought what you had been describing was that if
>| you had a pause in the stream, the CM11A now thinks you're sending microdims
>| so DIM_DIM without a gap gives a 6% dim whereas a DIM DIM with a gap is read
>| as a two microdims which are 2/210 or 1.2%.
>
>Although a lot of references use this description I do not believe that
>it is correct.  I think the initial DIM or BRI always results in a micro
>step regardless of whether it is followed without a gap by additional
>commands.  See:
>
>http://groups-beta.google.com/group/comp.home.automation/msg/0e3445aee7941493
>
>So the original poster's '+ X' would always be at least + 1.
>
>				Dan Lanciani
>				ddl@danlan.*com