Re: X10 signals can be TOO strong!

["Alan Vogel" <avogel2@xxxxxxxxxxxxx>]

"Jeff Volp" <JeffVolp@xxxxxxx> wrote in message
news:3yqgh.206476$Fi1.133150@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> "Alan Vogel" <avogel2@xxxxxxxxxxxxx> wrote in message
> news:uuogh.5921$Gr2.922@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> The inductor in series with the load is there to limit di/dt.  It was
>> probably required by the FCC to reduce EMI.
>>
>> I think this is all starting to make sense.  The highest di/dt transition
> is
>> when there is a heavy load and the conduction angle for the triac is
>> ~4.16
>> ms in from the zero crossing (50% dim).  This high current pulse must
>> have
>> coupled back into a high impedance node (either the zero crossing
> detector,
>> or the XTAL input pin on the uP).  Either way, the altered timing caused
>> abnormal conduction angles which showed up as flicker.
>
> Except for one thing:  The flicker continues, and becomes even more
> noticeable as the lights are dimmed even more.  As they ramped down to max
> dim, they would flash on every time another dim command was sent.  But
> remember, these X10 signal levels are WAY above those expected in a normal
> configuration.

I was talking to the Insteon module flicker issue in my last post.  The
XTB-II large output flicker problem could be resolved with a better dV/dt
snubber circuit in the module.

> I think the bottom line is that there is an acceptable signal level window
> for these PLC devices.  Too low, and control becomes marginal.  Too high,
> and dimmers can start to flicker.  The Insteon dimmers apparently
> misbehaved
> at normal signal levels.  I found X10 dimmers can also misbehave when
> confronted with signal levels several times higher than normal.
>
> Jeff
>
>