DMX Interface Refresh Speed

[DMXHack]

I am not certain of this, but believe this is a issue with the Velmen VM116 Interface speed.

When doing a chase; with FreeStyler 3.0 at 100ms Steps; I notice an occasional miss-fire with an LED ParCan (Chauvet ColorSplashJR)

In problem determination mode, I validated the length of the run to under 25ft, tried termination and still had a occasional burp in the sequence. In reading the VM116 API, I see that a setData( Long channel, Long value ) call is needed to send data down the bus, I assume that the DLL then is in charge of formatting the DMX Packet for delivery to the USB Device. W/O Source for the K8062 Interface DLL, I cannot tell if it has a set Timed Loop that it refreshes the DMX Packet down the line, or if the hardware itself does it.

So I suppose the real question is what interface is the best for very quick DMX packet delivery down the line?

[kikabyte]

In my opinion, not the Velleman, the more fixtures you operate, the slower the refresh rate, so the more chance you have of it missing a scene.

I would assume, an entec pro? Can someone add some opinion?

[djSupport]

the enntec pro has a built in processor to handle the dmx away from the computer which makes it very fast plus I think you can easily change the refresh speed

[digital1]

It is good to know that the minimum refresh time for a true DMX512 ( all 512 channels transmitted) depends on the transmission and could vary from a minimum of 26 milliseconds and up.
Your problem might not be in the transmitter but in the DMX512 receivers which might be programmed to receive a longer mark after break or need more break time to respond.
try the following dimmers by digitallighting they work with all kinds of DMX512 formats.

[remco_k]

I did'nt see this topic before, otherwise I would have include it in 2 other topics I started, wich both turned out to be related to this.

Actually many people (including me) had similar problems, regardless of the used DMX interface.
The source of it was a mix of things; in short:
-For most interfaces FreeStyler could not be configured to a maximum number of transmitted DMX channels, so it was always putting out 512 channels, taking about 26msec each 'packet'.
-Internal in FreeStyler was a refresh rate of 50msec(!) - thats kinda long if you have short sequence times or trying to flash a light at exact times
Together they are good for a delay that goes up to 76msec, furthermore there is the driver of your interface wich could also have some unknown delay.
So, we could assume that the total delay can go over 100msec. And there you have it; the source of the occasional miss-fire.
This >100msec is a way too long, reason for me to contact Raph (the developer).

See these 2 topics:
'Slow' response on flash button
FS always outputs 512 channels?
In short; in the next version of FreeStyler (3.0.2) there are 2 new things:
-For Velleman interfaces the maximum number of output channels can be set to 96, 256 tot 512.
-For every interface the refresh rate kan be set from 50msec(default) to 20msec.
See this post for the great results: Re: 'Slow' response on flash button