Re: [LCtalk] Falling off the network

[Fokko van Duin]

At 22:52 -0400 31-07-2005, mattyo wrote:
> > Note Be sure you use the latest lcudp-pack (included with LCedit+ 
> > v3.3), as it formats the udp packets in the right way for a LanBox.
>
> I'm not clear -- what do you mean by otudp alone?  I've got a bunch 
> of other stuff traveling on the network, using the new [mxj 
> net.otudp.send] objects. Might they conflict?

We never used the java networking together with otudp, it might 
conflict. More important is that you use otudp + lcudp-pack only once 
per LanBox device, else you will make a mess on the network (see 
below).


> > It looks like the box is crashed, AFAIK that is only possible by 
> > sending incorrect udp packets. I assume that only 1 computer is 
> > sending udp packets to the box?
>
> Aha -- actually the data is coming from 2 different computers.  How 
> would the box even know?

Different source IPs. You can do that, but then you send a DMX packet 
from two sources (this is steering one car with two persons :)


> the part that actually send it is pretty dumb, but here it is (all 
> it is doing is opening & closing a fader scroller):

This patch is working here without crashing, but....

1. It's flooding Ethernet completely, as you send packets without any 
speed limit!
2. It can only be used to set 1 channel at a time, as you bang out 
the buffer after each line change.


With UDP you can only send a complete packet of e.g. 500 channels, so 
a packet must be built. lcudp-pack is holding a complete buffer for 
maximal 3000 channels, and every byte can be set before you bang out 
the buffer to otudp.

So if you want to make your own fades, you must set your channels in 
lcudp-pack before you give a bang. This means for each channel there 
must be an independent line object, or you must calculate the new DMX 
value for each channel before sending out the packet (see our UDP 
desk example).

The moral of this story is that making your own fades in MAX is near 
impossible, unless you are dealing with not too much channels. 
Anyway, it's NOT simple.

The LanBox however has a complete desk with thousands of faders (even 
16 bit) built-in, and can very easily be controlled also with MAX:

1. set the manual fader time and type
2. send some set channel command for the new end values of your 
channels, and they will fade automatically to the new values, in the 
time you specified.

Have a look at our TCP/IP example, the right top slider does do that.


> Thanks very much for your help.  If all it is is routing all the 
> data from one machine, that's no big deal.  Out of curiosity, why is 
> that a problem?

Try steering one car with two persons :-)


> Also out of curiosity, are you looking to redevelop lcudp-pack so it 
> is compatible with the new java-based objects?

I don't know, I never tried it. Do you have any link pointer where to 
find these Java net.udp objects + examples? I have here MAX 4.5.4, 
but I can find anything on networking with java.

Regards,

--
Fokko van Duin,                     Creators of the LanBox-LC
CDS advanced technology bv,         DMX lighting controller.
http://www.cds.nl/                  http://www.lanbox.com/

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