renard and express

[ron d]

Will it be an issue to run 300 renard channels and an additional 100 or so lennox channels? i would bu using a ren 64, 11 or 12 ren 24's and 6-10 of rj's boards.

[rmonty]

Curious as to what DMX adapter you will be using and if you will be using multiple universes.  If you run all those channels on one universe then you could see some refresh timing issues due to the DMX protocol.  Also, the adapter will make some difference since that determines if the PC overhead will be used or the adpater will relieve the PC of some of the overhead.  Other than that, you should't have any problems.  I do not have that many channels to test with, but someone on this forum might.

[RJ]

many of the diy users run that many channels.  Where would the refresh rate problems be from, the software? The hardware always sends 512 channels in DMX so the refresh is the same if you have 1 channel or 512.

RJ

[vairmoose]

In doing the beta testing on the wireless, we have been running simple sequences with 512 channels (with effects)  at  50 and also some at 25ms using Vixen.   I've attempted to create a short sequence in LSP to do the same but with LSP being beta, it has not gone well.  Now that the capability to import from Vixen is there, I'll try again to create a large channel count sequence.    So far the lynx dongle has been fairly consistent at getting the getting the data out.  Now if the computer gets slogged down with several different programs running in the background it would probably change the results.  

Larry

[rmonty]

The baud rate of the output would cause the issue.  If you are trying to send out a lot of effect changes over a lot of channels, the limitation would be the refresh rate at which you could send out the updates.  Not a software problem, but a physical databus problem.  You just have to be careful if you start putting a bunch of 25ms time intervals in with a lot of effect changes.  50ms can fit 512 channels without a problem.  300 channels with 25ms time intervals with a lot of effects across the channels should work as the maximum transmission rate of all 512 channels is around 23ms.  Slower baud rates would take longer.

If he is using open DMX adapter then things change since that adapter doesn't have the ability to "store" and send the DMX data like the Lynx or DMX Pro.

EDIT:  Also, please note that the LSP DMX output plugins are setup at a refresh rate of 30ms.  You can change this value to lower, but we felt that anything faster than what the normal human eye can see (32Hz) is probably not needed.

[RJ]

Are you basing the numbers on the 115k or 230K  comm rate of the port? The virtual com port on the Lynx Dongle is not limited to this. It will send the data as fast as it can even thought you port settings are lower. So say you are opening the port in your software at 115K ...   You can send the data at almost 1000K to the port and it will handle it. You should be able to send all 512 channels of data updated to it every 25ms update of the DMX stream without issue with bandwidth to spare.

I am strickly talking hardware not software. But your port never sees a full buffer as the hardware is sending it out too fast (1 mbs) since the vitual comm port ignores all port settings and sends it out as fast as it can no matter what. So the software should be able to dump data at more than the 250k it takes to handle 512 bytes every 25ms.

In fact the data sheet say:

"By using FTDI’s virtual COM Port drivers, the peripheral looks like a standard COM Port to the application software. Commands to set the baud rate are ignored – the device always transfers data at its fastest rate regardless of the application’s baud rate setting."

I hope I understood what you were saying and did not just run off on a tangent.
 
RJ

[rmonty]

That is why I didn't answer the question with a resounding "YES!!!".  I understand the Lynx and DMX Pro adapters have no trouble with baud rate limitation.  But the post didn't specify what dongle was being used and I'm not going to say "YES!!!" and get a bunch of angry e-mails and support questions after the software has been purchased and they can't run it at 56k baud on a open DMX dongle or something similar.  I have been an engineer for a few years and have learned my lesson in answering questions in the absolute, especially without all the needed facts. 

[RJ]

That is why I didn't answer the question with a resounding "YES!!!".  I understand the Lynx and DMX Pro adapters have no trouble with baud rate limitation.  But the post didn't specify what dongle was being used and I'm not going to say "YES!!!" and get a bunch of angry e-mails and support questions after the software has been purchased and they can't run it at 56k baud on a open DMX dongle or something similar.  I have been an engineer for a few years and have learned my lesson in answering questions in the absolute, especially without all the needed facts. 

Ok got you.
Wanted to make sure the software did not have a limit we needed to be aware of beyond the hardware.

RJ

[rmonty]

The software  has sucessfully been tested with ~460 channels of LOR protocol that we know of, which is a lot more overhead than DMX.

Ryan