DMX question

[Apmccandless]

This morning I set up my ETC Nomad for a show for the first time (I have played with it in my basement before.) I ran into a problem when connected to an old EDI dimmer rack (early 90's vintage) the lights would flash on for about 5 seconds and then go out for 2. This only occurs on channels which were receiving signal. I tried on several different dimmers and had the same issue. When I plugged the rack into the house 2 scene preset no issue. I had no issues controlling anything on the other outputs of the opto splitter. I tried switching outputs on the splitter same issue. I tried to plug straight out of the EZ Kling into the Dimmer rack same issue. I tied switching cable between dimmer and EZ Kling.
Is it possible that the signal I am sending is too "new" a dmx signal for the dimmer rack? I know the standard has evolved over time. I remember using 9 pin serial control signal for computers and the baud rate increased over time. Also, some of the draft specs for DMX used a rs422 chip instead of rs485 but any documents I can find don't really give more info than that.
For the moment I am running all of the conventionals on the 2 scene preset and all of the intelligent on the Nomad. I would really prefer to use a single console if possible. Any insight you may have is greatly appreciated.

My setup is Nomad PC - Cat5 - Elation EZ Kling - Enttec 4 way Opto splitter
output 1 is EDI Dimmer
output 2 is Wireless trasmistter to LED PARcans
output 3 wireless transmitter to LED cyc lights
output 4 studio spot 250

Mac

 

[DuckJordan]

You are correct in the thought process of the DMX being too fast, There should be a setting on the nomad to decrease the Speed in which DMX is transmitted and should solve your issue.

 

[JD]

Commonly know as a "frame" issue. DMX itself didn't change speed, but there are some variances between equipment so issues like this pop up. DFD builds a frame smoother, although I forget where it is on their site. Most likely there is a way to decrease the frame speed on the board so that all devices are happy.

 

[soundofsparks]

I had a similar problem with some 1970s analog dimmers and an ETC Ion. We put a Fleenor Splitter in line after the demultiplexer (http://www.dfd.com/125e.html) and that cleared it right up.

 

[MikeJ]

Commonly know as a "frame" issue. DMX itself didn't change speed, but there are some variances between equipment so issues like this pop up. DFD builds a frame smoother, although I forget where it is on their site. Most likely there is a way to decrease the frame speed on the board so that all devices are happy.

I think you are thinking of the "dmx decelerator." The refresh rate, break length, and signal strength of DMX all fall within an acceptable range for the standard, but some devices don't respond well over the entire range. Often modern consoles tighten up the timing, for processor efficiency, and the "speed" is too fast for some devices. Sometimes, the signal may just be too weak, but this is probably not the case, because the opto-split buffers the signal for each output.

 

[llburg]

Unfortunately this doesn't help you, but I used a new Element (over nasty out of spec DMX cable no less) to an early 90's EDI MkVII rack with no issues.

Was that on for 5, off for 2 pattern repeated consistently? That seems like a really odd issue.

 

[jfleenor]

It seems I'm late to the party. Did you get your issue solved?