Does the 6C *generate* the DMX stream?

[ScottM]

I am considering buying a 6C. I need to control a very small number of channels (4, and probably never more than 8), but I have an unusual requirement - I don't want any sort of processing load added to the controlling PC. So I'm trying to determine if the 6C generates the DMX output itself, or is just a pass through device that is counting on the PC to generate the data at the required rate (like a Vellemen unit).

I know that generating DMX on the PC's CPU doesn't take much time, but the PC is already doing important, hard real time work every 20ms, and I don't want to introduce any timing issues for the existing code (or have the existing code affect the DMX generation). So I'm really looking for a device that generates the DMX on its own, not tying up the host CPU.

My other question is whether there's any problem in updating the levels of 4 (or 8) channels as fast as every 20ms. (I'm not very familiar with DMX). Changes every 20ms is the worst case scenario in my code, and I can add logic to send changes less frequently if I have to.

Thanks in advance.

[simonB]

Hi Scott

Our software transmits at a rate of 25hz.The SLESA-U8 allows you to adjust the speed between 0 and about 40Hz but the actual data sent is restricted to 25hz (a higher refresh rate will simply repeat values).

Do you need to trigger your scene from the PC? With the SLESA-U6 you can make a show on the computer, then transfer it over to the interface and run without a computer. Although the PC is used to send the DMX I am sure it will have absolutely no effect on your CPU performace, 25 packets of 513 bytes is absolutely nothing. Think about video playback of several MB's per second!