DMX timing ?

Questions or discussions about the Titan and classic consoles and software.

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PeterM
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Joined: 27 May 2011, 18:50
Location: Belgium
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DMX timing ?

Postby PeterM » 30 Nov 2011, 20:50

I have a question about the DMX timings on the Tiger Touch (Titan V5).
You can change DMX timings (break length, mark after break length) in ExpertDmx DMX module properties (desk in System mode).
But I have seen that you can also change DMX timing in the 'USB Expert Console' (tools menu) for both Dmx Panels.
The problem what I see is that DMX timings are different and seem not related to eachother (USB Expert Console <> ExpertDMX module properties).

So my question is : where can I change the DMX timing ?

Strange things happen in the 'USB Expert Console' :
the break length is set to 968us in the up/down box (but initial 990 shown as text value), MAB is set to 792us.
After a reboot of the console these values are always set these defaults again.
But for me these values are quite slow compared to the DMX standard.
DMX standard requires a minimum of 88 us for the break, and 8 us for the mark after break.
adamabcd
Posts: 20
Joined: 14 Oct 2004, 10:22

Postby adamabcd » 12 Dec 2011, 16:09

Hi,
Using Titan V5 on an Expert (testing with Lil Dmxter) I have found the following.
There does seem to be conflict between the 2 places where you can change the settings, one or the other not showing correctly, and sometimes boxes refusing to accept input.
I recommend that you forget about UsbExpert for making the changes, and just use the module properties.
The Break and MAB parameters usually show correctly in the module properties within a few usec once any changes have been made. Also I found that the settings are maintained betwween desk power cycles.
I would question the need for changing anything in the first place, unless you encounter a problem with the default settings. The default settings allow some fixtures which can not cope with full speed dmx to work without problem. The default settings output are actually 974usec break, 76usec mab (despite what is shown in UsbExpert).
Although these are about 10x the minimum allowable values, The actual refresh rate for the dmx is only reduced to about 95% of maximimum (ie 42fps compared with max 44fps). This means it only takes about an extra 2msec to output a full dmx frame. Seeing as the delay from pressing a button to the desk actually outputting probably varies fairly randomly between 40msec and 80msec. I don't think that you'll notice any difference by lowering the dmx parameter values.

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