RE: X10 Schema and Preset Dim

["Eric Vickery" <ericvic@xxxxxxxxxxx>]

Gerry,

I agree with most of what you are saying but if there is going to be
abstraction at all then I don't think the schema should be called X10. I
think there should be a more generic "lighting" schema. One side
benefit
of that would be that different xPL gateways could use the same schema
even though their hardware differs and then "clients" that wanted
to
turn on a light would only have to know 1 schema, unless they wanted
more specific functionality that a certain hardware protocol supplied.

One point I disagree with you on is that predim1 and predim2 aren't
standard X10 just because all the devices out there don't support them.
If you go that route then on and off are the only standard X10 commands
because not all devices support the other commands. I would also go as
far as to say the most (if not all) modern devices that use the X-10
protocol (not including devices actually from x10.com) support predim1
and predim2 unless they are a relay type switch.

To get back to my original question. Where should I assume that the
levels for preset dims will be in an xPL message? I have to support them
because my light switches use them as well as my thermostat.

Thanks,
Eric

-----Original Message-----
From: ukha_xpl@xxxxxxx [mailto:ukha_xpl@xxxxxxx] On
Behalf Of Gerry Duprey
Sent: Wednesday, December 14, 2005 12:43 AM
To: ukha_xpl@xxxxxxx
Subject: Re: [ukha_xpl] X10 Schema and Preset Dim


Howdy,

> That seems like an odd abstraction of the X10 protocol. If the
> underlying hardware is suppose to pick the correct then what command
> would you put in the xPL message, just a dim? If that is the case why

Well, not so much the hardware (i.e. an X10 switch) as the xPL gateway
to
the hardware.  Some hardware does this already (HomeVision) and others
don't
and require assistance by the X10->xPL gateway.

Thing is, some X10 devices have 16 dim steps, some have 32 dim steps and

some have 63 dim steps (levitons). Some can go directly to a level and
others can only do relative dimming. So it has always seemed logical
that
someone controlling an X10 device via xPL (where you are removed and not

directly in contact with the hardware) would specify a level 0-100% and
the
xPL gateway and/or hardware would be able to pick the closest possible
dim
level for the target device.

> does the X10 schema document not describe that and why are the preset
> dim commands in the schema. I think for an X10 schema it should
> reflect the actual X10 protocol, if it was going to be abstracted then

> (in my
> opinion) the schema shouldn't have been called X10.

Well, I can see two camps here -- the "just make xPL an virtual
wire"
where
you are expect to handled the various X10 vagaries on each xPL
"client"
and
the "let the gateway handle the fiddly low-level stuff" camp.
Short of
coming up with some sort of extensive and (I believe) confusing way for
a
remote xPL client to "know" what and how to dim each type of X10
device
(and
which X10 device address is what type of device), the former isn't
workable.

We're not talking about a lot of abstraction here -- just enough to
unify
the areas that have different implementations on different devices
(which,
believe is pretty much dimming and scene control -- everything else is
pretty well understood and consistent).

In fact, I'd go so far as to say that direct predim1 and predim2 aren't
standard X10 because not all X10 devices support them, so exposing is
again
an issue of device compatibility (I'd vote for them being removed from
the
X10.basic schema is I were a deity :-).

> Some X10 devices use
> the preset dim commands to invoke scenes, where would I put the preset

> dim level for those instances? If the level= value must be 0-100% then

> it would be a violation of the schema to use that name/value pair,
> wouldn't it?

Yep and that probably argues for an X10 extension of X10.basic that
knows
about scenes and such and again, handles figuring out how to invoke a
given
scene on a given device (again, scene activation differs from X10 device
to
X10 device) and keeping that "mapping" on the adapter side so a
client
can
just say "Activate scene 1" and not worry about the 3 different
ways it
would have to send that (depending on how varied the hardware on an X10
network is).

> I know nobody likes to document (me included) but with all this
> knowledge of the intricacies of the schema just in peoples heads it
> makes it very hard to get started using xPL.

I agree -- it can be very frustrating.  On the upside, there is a list
where
questions can be asked :-)  Looking at the schema, it does say levels
are
0-100, though other issues that you mention are not addressed.

One complaint about many volunteer project is the quality of the
documentation (or lack there of).  Very few people like to write
documentation at all.  Not that explains things, but the schema
documents to
date are more on the "minimal" descriptive side and could stand
some
clarification.  A good way would be to grab the doc and update it the
way
you think it should and send it to the list for proofing and once it
gets a
few nods, updating of the web page with that schema.

Another thing, which I know you're aware of because of our off-list
email is
that there is an effort underway to come up with a machine readable xPL
schema.  That would not only make schemas more parsable, but would help
to
more explicitly codify the schema and related documentation (the XML
files
will be translatable into HTML, human readable docs so everything
originates
from an authoritative source.

Gerry
--
Gerry Duprey
Ann Arbor, MI 48103
http://www.cdp1802.org



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