Re: I think they've done it again.

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sun, 25 Jun 2006 17:06:20 GMT, "Jeff Volp" <JeffVolp@xxxxxxx> wrote in
message  <gozng.250887$Fs1.208553@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

>"Marc F Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>news:1f7t92ll7oa28ospsqhfbm3bdvmhqe5nco@xxxxxxxxxx
>
>> Mike from INSTEON wrote in
>>
>http://www.techmall.com/post.asp?method=ReplyQuote&REPLY_ID=636&TOPIC_ID=180&FORUM_ID=9
>>
>> "The component that is in question is the choke coil. Repeated
>> INSTEON signals generated by the dimmer or controller were getting
>> into the triac and causing the flicker. We have increased the value
>> of the choke coil to attenuate the INSTEON signals that go into the
>> triac. "
>
>(some stuff snipped)
>
>> If, as it appears, the problem is with the high-current input choke and
>can
>> be solved by doubling the inductance, more turns on the inductor would do
>> the trick if that doesn't cause the inductor to saturate. But if a
>> physically larger inductor is needed, space will be a problem. The
INSTEON
>> dimmer cases are/can be made shallower than most other dimmers in part
>> because the choke is smaller.
>>
>> Because the response from INSTEON implied (to me at least, reading
between
>> the lines) that an add-on choke might resolve the flicker problem.
However
>> there isn't room for an add-on choke ("Lamp debuzzing coil") such as
those
>> sold by Lutron and others in all but the largest switch boxes.
>>
>> I have no problems with flickering lights (but did several years ago
prior
>> to installing any INSTEON owing to a inadequately torqued connection to
>the
>> neutral/ground  bar in the entrance panel).
>
>I can understand the inductor problem in their own device.  But I'm
confused
>by reports of other dimmers flickering during transmission of Insteon
>signals.  That's what pointed me toward possible early detection of the
zero
>crossing in the effected devices.
>
>Do you think the Insteon dimmers emit enough ringing onto the line to cause
>other dimmers to misbehave?  Why would that happen just during transmission
>of Insteon signals?  Or are the reports of other dimmers being effected of
>questionable validity?
>
>Jeff
>

[ First let me correct a stupid misstatement on my part.  The red wire is of
course the _load_ not line input as I wrote -- or none of the devices I
wired into my house would be working ... ;-) One of INSTEON's nice little
features is excellent and durable labeling so they are not to blame for that
gaffe.. ]

I glimpsed at the various threads  and with the little time I invested
wasn't able to separate the wheat from the chaff. My understanding from a
summary from Mike from INSTEON is that INSTEON concluded that there were two
device- (not protocol) related problems.

There is a second choke (actually marked L1) that is near the (presumed
coupling) transformer. I'll try to untangle the schematic. This statement
form Mike at INSTEON

   " We have increased the value of the choke coil to attenuate the INSTEON
signals that go into the triac"

can be interpreted to mean that at least one of the problems is related to
the PLC signal strength at the TRIAC and it is this other choke that they
are modifying.

Back to your question, one way to approach the analysis would be to
construct a spice model with both the INSTEON and another TRIAC based dimmer
in the circuit and explicitly model the AC line and neutral wires as
interconnects. Some of the reported problems could be related to high
impedance neutrals. The low inductance I measured for the INSTEON load
filter/choke(`18uH compared to ~44uH for even the cheapest X10 wall dimmer)
suggests that these will not be clean dimmers but I haven't scoped the
output.

I'll look at the reports some more so as to be able to respond more
usefully. I think that i understand your timing question and add the comment
that when I looked at line noise created by generic and X-10 WS467 dimmers
several years ago, I found that the highest peak voltages were measured at
about the 1/4 the RMS output IIRC.

Recall that an inductor 'stretches' the duration of a pulse, so the delay
caused by the L1 choke  might be long enough to trigger gate triggering in a
second TRIAC in a second dimmer when the delayed/stretched INSTEON PLC
signal is _added_ to the TRIAC noise from the INSTEON TRIAC at some time
significantly after zero crossing and that signal is not sufficiently
attenuated (there are two issues here; timing and noise/signal strength.)

Later ... Marc
Marc_F_Hult
www.ECOntrol.org