Re: I think they've done it again.

[nobody@xxxxxxxxxxxx (Dave Houston)]

If the subject devices are older X-10 manufactured Leviton label devices,
some are known to do odd things when there are noise spikes on the line.

"bruceR" <nospam@xxxxxxxxxxxxx> wrote:

>FWIW, perhaps I should mention here that the "flickering" - at least in my
>case - is a very brief (guessing 100ms twice) brightening of a dimmed load
>rather than going dim or dark.
>
>  <nobody@xxxxxxxxxxxx>wrote:
>
>> Yes, I think Dan Lanciani and I are saying something similar but I'm
>> suggesting that the triac noise at mid-cycle is triggering a false
>> reaction by the PIC (assuming it's a PIC) that then prevents it from
>> turning on the PIC during the following half-cycle(s).
>>
>> I have a NEC Multisync XV15 monitor which outputs noise of an unknown
>> (to me) spectra. When connected to the same power circuit as the NEC
>> monitor, the initial Powerlinc 1132B goes deaf to the powerline. With
>> the 1132B powered by a different circuit it works OK.
>>
>> I have 3 Lamplinc 2000STW modules. None work reliably on the power
>> circuit with the NEC monitor - their LEDs flash randomly and they
>> respond to PLC commands intermittently. All work normally when
>> powered by a different circuit or when the NEC is powered down.
>>
>> At the moment I have two Insteon Powerlinc 2414S PC interfaces and two
>> LampLinc V2 2456 modules. The LEDs on all flash randomly when
>> connected to the circuit with the NEC monitor but are rock steady
>> when powered by a different circuit or when the NEC monitor is off.
>>
>> Plugging the NEC monitor into a Leviton plug-in filter reduces the LED
>> flicker on most of the devices and 2 of the 3 Lamplinc 2000STWs
>> appear to work OK. Adding a John M. Jones homebrew filter (just the
>> choke from an X-10 lamp module) in series with the plug-in filter
>> eliminates the LED flickering on all of the Insteon modules and the
>> 3rd Lamplinc 2000STW starts working.
>>
>> No noise shows up on my 'scope using the ACT Scope-Test2 (tuned for X-
>> 10). Triac switching transients from my dimmers do show on the
>> 'scope. All of my X-10 modules work with no problem in the circuit
>> with the unfiltered NEC monitor.
>>
>> I suspect they have a fundamental design flaw that causes their
>> devices to be affected by out-of-band noise (or by very low level in-
>> band noise) and that they have carried this flaw through all of their
>> designs.
>>
>> The published signal sensitivity spec for all of their modules is in
>> the 10mV or lower range so this might also be a factor.
>>
>> With the 1132B and the 2000STWs, it appears that they get into a
>> state where they are expecting additional input that never comes or
>> that they get out of the state but another noise pulse triggers it
>> again almost immediately.
>>
>> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>>
>> > > An undersized choke could allow this noise to reach the PIC
>> > > (in the subject switch or in other devices on the line) and this
>> > > might cause the PIC to stutter and miss a half-cycle or more.
>> > > (The PIC has to actively turn the triac on for each half-cycle.)
>> > > Earlier Smarthome designs (e.g. 1132B and 2000STW) have
>> > > been overly sensitive to disruption by out of band noise.
>> >
>> > I believe Dan had also mentioned this unwanted PIC interaction as a
>> > possible cause for the flickering.  FWIW, this seems to be the
>> > likely explanation because reports indicate the V2's are emitting
>> > EMI that's extending well beyond the local circuit.  Something's
>> > leaking out of the V2's that's strong enough to fool nearby devices
>> > into behaving erratically.  There's not much other than EMI and
>> > voltage fluctuations to explain flickering.   I believe I read that
>> > the EMI placed on the line by a triac is 90 degrees out of phase
>> > with the original AC cycle.  Is that what's causing nearby dimmers
>> > to flicker?
>