Re: CM15A & receiving dim

[nobody@xxxxxxxxxxxx (Dave Houston)]

Neil Cherry <njc@xxxxxxxxxxx> wrote:

>I'm not sure if anyone has resolved this but I'm trying to decode
>simple dim commands being sent from the ti103 and received by the
>CM15A. If I send 1 DIM ($>28001N01ND40ND40F8# or N1 NDIM - note these
>are continous dims for a single command) I see:
>
>5a020086
>5a03020b84
>
>As far as I can tell (no X10 doc still) the first line is 5A (received
>from the power line) 02 (2 bytes follow) 00 (it's an address) and 86
>(X10 address - N1). The second line is 5A (power line), 03 (3 bytes
>follow), 02 (either 2 more bytes of an ID for DIM/BRIGHT), 0B (Dim % -
>still need to figure out the math) and 84 (NDIM).
>
>I've also sent multiple dims:
>
>1 DIM = 5a03020b84
>2 DIM = 5a03020b84
>3 DIM = 5a03021684
>4 DIM = 5a03022184
>5 DIM = 5a03022c84
>
>Not sure what the math is on these. I'm guessing value/256 * 100 but
>that's just a guess. Any ideas?

It depends on the receiver (and manufacturer) but I worked out the math for
an LM465 using a 100W lamp and my Kill A Watt meter. See...

     http://davehouston.net/micro-dim.htm

See the CM11A documentation for an explanation of the bytes from the CM15A.
The third byte (02 in all but your first example) is a bit map that
indicates which of the following bytes are addresses and which are
functions.

All of my switches are Insteon ToggleLinc relay types (controlling old
fluorescents) so I'm unable to test this for an X-10 dimmer switch. You
would have to temporarily wire the dimmer switch to an outlet and then use
the Kill A Watt and 100W lamp in the outlet.

Note that the CM11A documentation says 22 DIMs equals 100% but the lamp
module never goes to 100%. The maximum is 96%. There's no measureable
difference between 21 & 22 contiguous steps using both the Kill A Watt and a
true RMS voltmeter.

Earlier versions of the CM11A firmware output after each dim/bright command
rather than sending the cumulative total. I haven't confirmed this but I
think there was no way to accurately estimate the actual level because you
couldn't tell whether the dim/brights were contiguous.

Charles Sullivan has indicated he sees a difference depending on whether the
DIM starts on a ZC rising edge or falling edge but I haven't verified that.
(It is on my lengthy ToDo list.)

http://davehouston.net
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