Control/Dimming DMX Ghosting issues

[PatrickGrimes]

Ok - Here goes...

First the specs - Element board, 5pin out to wireless DMX transmitter. DMX receiver above deck connected to a series of LED pars via 3pin. 3pin to 5 pin converter into portable dimmers hung over deck. + 4 moving head fixtures front of house with only wireless receivers.

The Problem.
The LED pars all work great. The first connection out of the 3pin daisy (no matter which dimmer that is!) will operate perfectly IF the first channel on the dimmer is active. ie. Dimmer has four channels, starting address 1. Bring 1 up and then 2, 3 and 4 are all happy. Bring 1 to zero and try to operate anything else and all fixtures flicker and ghost completely randomly. Add 1 back in (even at 1%) and everything goes back to normal operation. Granted, I can set a prewarm for channel 1 at 1% forever, but that seems like a ridiculous thing!

The Trouble shooting steps I have tried.
First I eliminated the wireless and the 3pin from the picture and connected 5pin from board directly to the 5pin dimmers above deck. Everything worked perfectly.

Second, I added the 3pin pars back into the mix by going 5pin to 3pin dmx wired directly to the chain of LED pars and then 3pin to 5pin out of pars and into portable dimmers. Everything worked perfectly.

Third. Added the wireless receiver back into the mix and the ghosting started once more - So... Must be the receiver! Replaced the receiver and same issue with new receiver!

Fourth. Since the wireless units act as transmitters and receivers, I swapped the one a the board with the one above deck. Same issue.

Fifth. replaced the physical adapters (just in case!) Same issue.

Sixth. Attempted to run the 3pin to 5pin conversion into a different (And newer) portable dimmer over deck and here is where things got interesting. I patched the 3 pin into a dimmer whose starting address is 17. Thereby bypassing several other dimmers... Same issue! If the first channel in the series isn't sparked at all, then everything goes haywire. Add 17 at 1% to the cue and everything goes back to normal.

Huh? Truly stumped. Termination issue?

 

[derekleffew]

Quite peculiar.

If it were a terminator, DMX issue, having the first dimmer be at a level above 00 wouldn't remove the symptoms. That said, terminating every DMX stream is cheap and easy insurance.

You didn't state the make and model of the wireless DMX or of the shoebox dimmer s. Did you try changing the address of the dimmer pack(s)? How many are there, and if more than one, do dimmers on other packs "flicker and ghost completely randomly" when dimmer#1 on the first pack is not >00?

Have you tried putting the PARs (what male/model are they?) before the dimmer pack(s) in the chain?

.

 

[PatrickGrimes]

Wireless DMX are a no-name generic. there are 4 total in the system 2 in front of house controlling the 4 moving head fixtures and one above deck plus the transmitter on the board. Four movers are all perfectly happy! In fact, the LED pars are all happy when they are in the chain and they are currently the first thing in the chain off of the wireless- just the conventional dimmers are angry!

The shoeboxes are leprecon ULD 340s and there are 8 of them. The pars are Chauvet slim par 64s.

Everything conventional goes haywire when the first isn't set to any value, but only after you have changed the light's level... ie fixture on channel 12 won't be acting oddly until I move slider 12, then it sparks and starts misbehaving. Add to it channel 1 and it behaves. Take 12 out, then take 1 out and everything will stay off, but take 1 out and leave 12 up - it will start flickering. add to it 13-24 and they all misbehave until 1 is added at any value above 0. when they all join the party and play along!

 

[hobbsies]

I had a similar issue with my intelligent fixtures. The cause, I found, was that the LED pars were set to the wrong mode and were overlapping addresses. It caused the moving lights to freak out (spin every which way, rotate through every color, gobo, prism, etc constantly), and pars to ghost. Once I had set all the pars to the correct mode, everything started working as it should. Don't understand why a few pars with overlapping addresses set to the incorrect 6channel mode would cause the entire DMX chain to fail, but now I know.

 

[tdrga]

Wireless DMX are a no-name generic.

Does your wireless DMX transmitter have a setting to transmit fewer than 512 dimmer slots? If so, it could be dropping the first slot (address # 1) when it is at 0 value and shifting everything down to lower slot numbers, which obviously completely screws up any addressing down the line. Very bad behavior, but if they are "no-name", you never know what strange operating modes you might have.

-Todd

 

[PatrickGrimes]

Doesn't seem to have such a thing happening as the moving heads are functioning perfectly... The craziest part, now that I think on it, is that the LED pars, which are physically first in the chain, are addressed in the 80s, and they are perfectly happy, even when the rest of the dimmers 2-30 are going haywire. It might be that I have to set the show to pre-warm channel 1 at 1% even in blackouts. Ridiculous!

patrick

 

[Chris15]

Add my vote to the wireless unit doing something funky.
Could you not just add 10 to all of your dimmer addresses and not use ch 1- 10 and have them permanently parked at FF?

My suspicion is that they've poorly chosen their modulation scheme and transmitting all zeros means that it cannot lock properly to the signal and so it's going funky. By the time it gets far enough into the frame to get to your LED channels it's gotten its act together and is behaving...