Re: X10 APPLIANCE MODULE

["John Gilmer" <gilmer@xxxxxxxxxxxxx>]

"George Pontis" <gpontis@xxxxxxxxxxx> wrote in message
news:MPG.1d55f127bade4e6b9897ce@xxxxxxxxxxxxxxxxxxxxxx
> In article <42ec0f47$0$11911@xxxxxxxxxxxxxxxxxxxx>, gilmer@xxxxxxxxxxxxx
says...
> >
> >
> > >
> > > Does the appliance module use a mechanical relay to close the circuit?
> >
> > Yes.
> >
> > BUT the electronics that operate the relay can sometimes be messed about
by
> > an electronic load or just plain flourescent fixtures.
>
> Not the old-fashioned fluorescent fixtures, but some of the new ones with
> electronic ballasts.

    Well, "it depends!"

With relatively small fixtures (15/20 watts) with a conventional starter and
balast, I have had situations where I had a hard time turning them off and
KEEPING them off.

> This is due to some leakage current slowly charging up the
> ballast until it reaches the point where it can flash on for a fraction of
a
> second. This fools the load sensing circuit into thinking that the user
has closed
> the switch.

That sounds about right except that it happens with CONVENTION flash tube
"starters" also.

>
> >
> > There are "fixes" for this but in my experience they don't really work.
> >
>
> The fixes involve opening the modules, then cutting specific leads or
desoldering.
> It worked for me in one case. The Smarthome Appliancelinc allows one to
> programmatically turn off the load sensing, and has a quieter relay. I
have one
> that works reliably (more reliably than X10 pro modules) with a
fluorescent load
> having an electronic ballast. I couldn't say that it is immune to that
problem
> though.

Exactly!

One would like to think that "they" would market a "dumb" module that would
completely ignore the load and only respond to X10 commands.   Or, perhaps,
have an extra switch that does that.  But NOOOOOO.

>
> > Oh, the relay is somekind of step or latching design.   "Next time" one
> > breaks, I will check it out.
>
> Yes, a simple latching relay. Noisy but effective. To save you the trouble
of
> taking one apart to check it out: http://www.geocities.com/ido_bartana/

Perhaps YOU should check it out.   One of the pictures jogged my memory.
It's a STEP relay:  each time the coil is pulsed it opens if it was closed
and closes if it was open.   The electronics "senses" the voltage drop
across the contacts to get feedback so that the electronics "knows" whether
to pulse the coil if it decodes an "on" of "off" command.   If the module
"knows" that the contact is closed and receives an "on" command, it does
NOTHING.

Trouble is, of course, is that certain "light" loads may make the closure
detection circuitry not work reliably: the electronics may "think" that an
"open" contact is actually closed and give it an extra pulse.

A "dumb" module would actually require an additional contact on the relay to
determine it's position regardless of load.    Since most folks don't really
care about such stuff, a "dumb" module might well cost 4 to 5 times the cost
of the standard appliance module.



(A latching relay has TWO coils:  one operates the relay and the other
"unlatches" the relay.    These are MUCH more complicated that a simple
sequencing relay.   These "sequencing relays" used to be commonly used in
toy electric trains and let the operator reverse the direction of AC powered
toy trains.    DC operated trains reversed by just changing the polarity.)