Design Spot 250 - DMX Error w/wireless DMX

It would have to be a polarity issue causing them to behave erratically. I to checked all the equipment you are using and the polarity matches up. Did you try going from the splitter to just one design spot at a time? The only other thing I know to try is reverse the cable going from the splitter to the design spots, and if they still act crazy, the problem is your wireless unit.

If the fixtures are responding intermittently/erratically, then I really don't suspect a polarity issue, because polarity is kind of an all-or-nothing deal. Either they respond, or they don't.

You said that you made a terminator. What type of resistor did you put inside (wattage and resistance ratings)?

I would have to disagree with you LighTech. Usually if the polarity is reversed, nothing happens and you get no response. But, I have on many times flipped the polarity switch and watched the moving lights go crazy.

Could it be that wireless DMX and splitters just don't get along? I have never heard of anyone running a splitter back through a wireless DMX system before. Then again, I have never used wireless DMX myself, don't trust it. I might be going out on a limb here, but when you by-passed the wireless, the problem was solved. So I believe the problem to be in the wireless somewhere.

Also, when you tried the Seachangers, were they in the same port as the DS 250s were or a different one? Might have something to do with the ports.

Personally, I would stick with wire DMX. Almost no chance that something can go wrong when it is up and working. Something as simple as an object moving in between the transmitter and the receiver can mess with wireless anything. You also have a splitter at the end of the line, and I don't think you have another 750+ feet of DMX after that. DMX is good for about 1000 before you need a splitter. You also terminated the line, which helps correct problems as well. Always a good idea to practice this, even with short runs since it is so cheap to do.

The Seachangers worked just fine on the same exact port (and even same DMX channels) as the non-working Elations. However, an important thing here is that the Elation is a 3-pin DMX and the Seachangers are true USITT DMX-512 5-pin, so maybe there's another issue there as well.

I'm guessing there's some kind of parity or voltage issue with the wireless setup and the Elations just seem to be more sensitve to it than other equipment (or the simple fact that they are 3-pin and not 5-pin equipment).

I wasn't so much looking for a solution; but just to see if anyone else had experienced similar issues using wireless DMX and a splitter box with the Design Spot 250.

-Chris

About the terminator I built, I used a 1/2 Watt 110ohm resistor on a male XLR plug, pins 2 and 3.

I did try running the units in individual, from all the different outputs, and "daisy chain" and had the same problems. I haven't had the guts to try the units with different polarity (swap pins 2,3) since all the schematics matched up and I didn't want to fry or otherwise screw up any of my new equipment.

-Chris

Hi Chris,
A few things here..
The schematics on the 3 pin vs. 5 pin are exactly the same. We have the new Design Spot 250Pro which uses both 3 and 5pin XLR connectors.. In the 5pin, pins 4 and 5 are not used so it makes it similar to a 3 pin cable.

I would agree with the eratic behavior being polarity difference.
However when you connect it to the DMX splitter, you should have red and green lights on when you connect a fixture to them.
Study those lights when you connect the sea changer and the Design spot 250. do they light up differently?
I checked out the manual on your wireless system, and your right the plusses and minuses add up. But I would still make a polarity switched cable.

Last but not least..I had a similar situation when the data transmition was just not strong enough.
The Design Spot's have a stand alone mode. Which if you bought them new recently, this mode should be off and not be in effect.
However for some reason this mode may be on.
Example if the lights are on with no DMX do they move around or stay still?
If the signal is not strong enough and the stand alone mode is on. then the stand alone mode will take over making the fixtures act eratic.

Aside from all of this everything should be good.

But then again.. if the stand alone mode is off.. and the fixtures stand still when no DMX is present.. then you plug in the wireless to the light and it starts acting eratic.. this means that the wireless is transmitting something to the light.. its just not correct and a polarity switched cable may just do the trick.

John is correct in that 3-pin and 5-pin DMX the only difference in the connector. The difference between XLR and DMX is impedance. Are you using 110 ohm 3 pin cable or regular XLR? The loss of signal through the wireless coupled with a loss of signal through the XLR. This might be the problem since you said 5 pin DMX was fine, and it will have an impedance of 110 ohms if it is a true DMX 5 pin cable.

Couple of things here:

1. When connected to the WIRELESS DMX, both green and red LED's on the Splitter show solid and bright.

When I connected the lighting console directly to the splitter (about 3ft of DMX cable), the LED's were dimmer and slightly flickered. (and the Elations functioned normally). (The same occured with the 350 ft run; no change in the LED's).

2. Both Elation 250's acted in exactly the same manner when connected to the wireless. The LED readout was showing DMX signal being recieved. When the DMX was turned off or disconnected, the units return to normal (no movement). I checked both units and disabled any stand-alone modes.

The cables I am using for the Elations are the supplied 3 pin DMX cables (about 10 ft). I swapped out other 3 pin cables with no luck.

All other cables are specifically DMX cables and there are no microphone cables, etc, in the entire rig.

When I get time I'll try reversing the polarity of the 3 pin cables and see if that does the trick, but I imagine that will mean I will have to do similar things to any other 3 pin devices I attach to this rig in the future. I think I'll stick with the wired DMX I have running now and keep the wireless DMX reserved for future use (as many have said, the reliability factor of the wireless may be an issue in the future).

Thanks for your help everyone. I literally spent 2 days straight trying to figure out the problem, finally gave up and just ran a cable for the DMX. My Elations are working wonderfully and, if the budget allows, I hope to buy more in the future.

-Chris

Chris sounds good. But something just came to mind.. That cable that came with the lights has given me similar problems in the past. I don't know what it is.. but I throw that cable away.
and chances are the other 3 pin cable may have been mic cable.

I would say try and order some 3 pin dmx cable and see if that solves your issue.

Best regards,