Looking for DMX512 schematics

[RussMartin]

Since posting my reply, I had the opportunity to talk with the US sales rep.

Apparently, with the OpenDMX, the computer is having to do all the timing chores in software. How close the result is to the "standard" 44 frames per second depends on how much other stuff the computer is trying to do at the same time. When too many demands are made on the computer, he said it starts "dropping" packets.

He also suggested that the USB DMX Pro is a way to eliminate the problem, for $95 US over the cost of the OpenDMX.

http://www.enttec.com/index.php?main...name=dmxusbpro

Thanks for helping me out with this!

[bcd]

Russ,

44 times a second is not a bad refresh rate. The DMX spec allows upto a 1Hz refresh rate, although the fades look a bit 'jumpy'. I own a Martin Lightjockey system and it has the options for 44Hz, 22Hz and 11Hz transmission.

44Hz is fine for most moving rigs. Personally I have code that will transmit DMX from a PIC at 80Hz, but that runs a tight loop with only 24 channel frame, but have found that a quick refresh can sometimes freak out some of the cheaper Chinese style scanners.

The Enttec stuff is great, but I would recommend the USBPro interface as it is also isolated and has some more funky software options.

From the Enttec site on the USB Pro: http://enttec.com/index.php?main_men...name=dmxusbpro
<snip>
# Refresh Rate configurable from 1 to 40Hz with a full 512 channel frame
# Break configurable from 96uS to 1.3mS
# MaB configurable from 10.6uS to 1.3mS
</snip>

Bill.

[grich]

sorry my mistake