Re: Xpl-Dmx.Lcd

["g8kmh" <lehane@xxxxxxxxxxxxxxxxxxx>]

--- > > I'm still not sure how you plan to do this?
> > Are you going to use a new start code and a DMX channel per
character
> > position?
>
> Nope.......The idea at the moment is to have a seperateprograming
connector
> which can be used  to download messages using xPL ...When the user
inserts
> the programming dongle the pic will start looking for xPL commands
and when
> the dongle is removed it will revert to looking for Dmx
commands..........So
> the lighting levelsent to the lcd channel would relate to a message
in a
> message table...The xPL app would have a copy of the current
message table
> for reference,otherwise it would be hard to remember message 20
is"garage
> door is open" etc.........
> Of course message 20 would be getting sent to the dmx lcd
continually until
> a new message was sent ,but ther pic would just compare to current
message
> and ignore it if they are the same.....

OK, you're effectively going to use the DMX line as a multidrop RS-
485. Personally for a display, which is dynamic, I'd either go the
extra mile and put it on its own dedicated 485/232 line or go
Ethernet. Then the display could respond to osd.basic - I use osd
messages for status, news and weather, currently on the Tivo and
Squeezebox but later 4 line LCD.

>
> > Are you going to use a new start code and a DMX channel per
character
> > position?
>
> This would be a better approach  but im not sure if the Milford Dmx
Tx unit
> will recognise and sent out different start codes....This approach
would be
> more flexible.....Only problem i see is if you have more than one
dmx-lcd
> how do you indicate which one must capture the data to display ??
unless you
> use say the first byte as unit number and after that data...???
>
> Frank
I guess you'd use a different start code. I'm not familiar enough
with real world DMX to know whether you can implement a solution with
different start codes in one DMX universe. If you can then that would
reduce the update rate overall. You could then send 255 characters
dynamically to the display(s). In the end though, it is using DMX in
a way it wasn't intended for.

Lehane