Re: DMX and xPL

[Kevin Hawkins <lists@xxxxxxxxxxxxxxxxx>]

Frank Mc Alinden wrote:

>
>Would be nice to have a hardware interface for xPL to
Cbus....????....Wonder
>how difficult it would be ....??.....The main issue her would be
getting the
>protocol from Clipsal..........
>
>Frank
>
>
>
>
Who's interested in this ?? I have always said that if there is
sufficient demand I would produce an xPL version of my board - it costs
a lot to produce a surface mount board, CE approved and to join the
C-Bus enabled program. Plus there are the licence fees and two bought in
modules (processor and C-Bus SIM) plus case tooling. That's not even
considering  the coding time. The xAP versions of the board have also
been very low quantity although there are a couple of  possibilities now
floating around that might change this.  I knew this but was prepared to
do it as I needed it for my own setup. Obviously having extra sales
through an xPL version would be attractive but there needs to be a dozen
or so takers and I don't think we are there yet - are we ?? If there are
enough takers I would do this.  :-)

The profit margin on the board is quite small as I tried to make it
appealing to everyone here on UKHA.  Any commercially available version
would be considerably more.  The lower cost solution is obviously to use
a PC application as middleware as in a direct connect to the RS232
module or via C-Gate which is how my first version at UKHA 2003 worked.

Meanwhile if you did want a hardware solution you could always use
the xAP C-Bus controller & bridge between xAP and xPL using the inbuilt
functionality of xPL HAL.  A bit of scripting work will be needed as the
environments have differing data in the packet structures -  I guess it
may be do-able. Anyone up for this ??

Adding xPL is not difficult although it does require a whole
different style of operation as the xAP version uses the hardware sub
addressing and UID values along with multiple body parts that were not
carried over in  the xPL fork. I am guessing I would instead support a
similar schema to the one used via the xPL to C-Gate connector - or is
there a specific lighting control schema available in xPL I wonder ??
I haven't looked in detail at this and I have noticed a trend towards
things sitting within one sensor.basic / control.basic schema rather
than more specific functional schema areas like lighting, heating  or
security etc.    I guess the same decisions exist with regard to how xPL
might implement any DMX integration. I shall keep an eye on how this
progresses and see if something useful drops out that will be applicable
to C-Bus and easy to implement from where I am currently.

As the number of C-Bus users increase and xPL too becomes
implemented in more networks hopefully the number of potential sales
opportunities will be there and this development work will be an easy
choice.  Ironically DMX  might actually detract from this as a lower
cost option. But it would be nice to be able to implement lighting in
many more places than you can justify C-Bus.  I'm dead keen on a DMX /
xPL  gateway although I strongly favour an embedded standalone solution
that would work without a PC helper application.  If anyone were to
think of writing this in C on an embedded controller  they might even be
able to use my board base hardware which would take away a load of the
practical headaches - including the killer of CE approval. The board has
adequate I/O, speed and code space and removing some parts eg the C-Bus
connectivity  would bring the cost down.  (BTW The board is Rabbit 3700
based 512K RAM 512K Flash - 4 serial ports (RS232/422/485) plus parallel
I/O , lcd display & keypad circuitry). If anyone is up to this drop me
a
line and I can discuss the bare board costs.

Kevin

PS  G8KMH 73's G8KIO !