Re: x10 Help

[nobody@xxxxxxxxxxxx (Dave Houston)]

Frank Mc Alinden <Frank.Mc.Alinden.2z7e8h@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

>
>Hi Guys
>
>Just an update....
>Received my Maxi controller from Laser today so i plugged it and the
>Elk ESM1 into a power strip next to my pc and triggered some x10
>signals on the Maxi to see how many bars would light up.....Only 2
>would light up so i opened the ESM1 and preceded to adjust the pot...It
>appeared to have been set fully in one direction....Adjusting it fully
>in the other direction caused the x10 led and one bar to be lit most of
>the time without any noticeable change when the Maxi send x10
>commands....so i set the pot back to its original setting......
>
>I took the Maxi and ESM1 and plugged them into an outlet in the kitchen
>and when i trigger x10 commands from the Maxi i get full scale most of
>the time ;-)
>Looks like my pc +ups,s are loading the signal.....
>

When Paul Beam was designing it, he read the X-10 literature and saw that it
said the signal level was 5Vpp. When he measured a few signals, he found
they were actually 10Vpp. Being new to X-10, he assumed that the 5Vpp was a
mistake and that they meant 5Vpk so he calibrated for full-scale at 10Vpp.
When ELK bought the rights to the design, they changed the calibration to
read full-scale at 5Vpp.

I don't think there's any limit in the US/Canada but CE limits PLC signals
to 5Vpp and most European modules have been redesigned in the past 7-8 years
to meet those requirements.

There's also the issue of attenuation by the 120:12 or 230:12 transformer.
Since it depends both on the DC level (based on the AC input) and on the
bandwidth characteristics of the transformer, it's impossible to predict
without knowing the transformer details - calibrating to some known level is
the only way to establish a baseline. Of course, the baseline can be (within
the limits of the circuitry) anything you desire but you now can relate any
less than full scale reading to a known level.

I'm glad to finally have confirmation that changing the transformer works. I
was sure it would but its always better to have a thread like this (by a
surviving hacker ;) to point future wannabe hackers to.

The output levels of some US/Canada transmitters are shown here...

     http://davehouston.org/x10-sig.htm

Most of the newer modules are closer to 5Vpp while all of the older designs
were 10Vpp.

The great value of the ESM1 is, as you've discovered, that it takes the
guesswork out of the mix and allows you to quickly determine what is
attenuating the signal.

http://davehouston.net  http://davehouston.org
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