Ion DMX/dimmer communication issue

Of course my first response would be to  call Tech Support. (1.800.688.4116) But in the meantime...

I've run into this twice with my Ion while touring across the country. Both times the building told me that it only occurred with Ion's. Hogs were fine, Older ETC boards were fine, but Ions were the issue. 

I spent a bit of time with ETC about it, but as I was just a touring company, I could only go so far with the troubleshooting as it got to the point of having to dig though the theaters dimmers.

In one case, it was as you described. Of the 3 in house dimmer racks, only lights on one rack would start to flicker / pulse a bit. 

In the other theatre all of the racks pulsed. 

In the theatre where all of the racks pulsed, at ETC's suggestion, I was able to get around the problem by snipping the common on a DMX cable. It got me through the night and apparently proved to ETC that it meant there was a wiring issue with the building.

In the building where only 1 rack was pulsing, I ended up using their in house Expression 3 console as a go between. DMX out from the Ion to DMX In on the Insight. Then DMX out from the insight to their dimmers. It took some setting up / config, but it made it so I could do my show that night. 

So long story short, its probably a wiring issue in your building / racks. Someone with a better comprehension of DMX can probably chime in and give you a better sense of what to look for. 

As Benjamin suggests, this is likely to be a cable issue. It's highly unlikely this is related to the Ion.

I would first check that link is properly terminated at the dimmer end (possibly a switch on the final rack). If you are happy that it is terminated correctly, try and check the whole string for damage, there may be a nick in a cable somewhere.

Dan

An update on the information:

(and I will be calling ETC this evening once the console is brought to the theatre for testing)

-the dimmers are a strand brand (but I do not know the make yet)

-the dimmers were reset to no effect

-the equivalent of an opto-splitter was used to no effect

-all the DMX outputs were tried.

I do not know how to find out if the dimmer racks are terminated, but I am hoping knowing the model will lead me to useful specs regarding this.

The only suggestion I was given from someone at the theatre to try is to try the patch bay on stage verses the patch bay in the booth to try to eliminate it as a board problem. As well I might be in touch with Solotech, the company we purchased it from, to try to borrow a DMXter (another suggestion from an electronics/DMX instructor).

And thank you both for your help and suggestions!

-

Christina S

National Theatre School of Canada, Monument National

One of the first times I did an Ion Installation, we ran into something similar (or the exact same). What we determined to be our issue was that the building power that our console was on, and the power that the dimmers were on were using 2 different grounding rods.  (In our situation, part of the building was an expansion wing).

 

Our solution was to disconnect pin 1 (reference), and then the system worked.  Another solution would be to put an optical splitter in-line between the console and dimmers. 

 

Hope that helps.  Look forward to an update as to what you find.

I realize you are still developing information related to your problem- but I would have a few other questions to ask if I were the tech helping you.

 

Are you sending DMX from the console directly into the dimmer racks, or is it going into a Strand DMX node? 

Also, are there any other controls for these lights like a button station on the wall for houselight controls?

When the lights flash or flicker, do they all flash randomly like a disco or night club, or are they all pulsing on and off together in a slower pulse (i.e. lights on, 2-3second delay, lights off, 2-3 second delay lights on?)

Depending on the equipment you have, and the type of flashing/pulsing you are seeing, I might have some Strand related things you could check on.   This would especially apply if the rack is a C21 and the architectural system is Strand's Vision.net controls. If you have any Strand N21 DMX nodes in the system, that can also be related to this problem.  It might not be the ION that is the main problem, but the configuration of the Strand system.

Please let us know what you find if you manage to resolve the problem outside of the forum. 

 

Thanks.

 

 

The dimmers are Strand CD80 with a C21 processor.

Yes there is a mount on the wall for controlling the house lights manually that overrides board control when on.

The pulse is subtle and more or less together. I noticed it only at a low level where the level change was more obvious. Almost like candle light, if you will.

We did discover something very peculiar, however, which I will try to explain, that we believe cleaned up our DMX line/signal. We plug the console into a patch panel in the booth. This panel (along ith DMX 1 that goes to the dimmers) has DMX 3 input and output runs that goes to the stage and back. (DMX 2 doesnt work) Right now we had to set up the console while another production is going on so there are lights set up on stage, two of these being claypacky stagecolour 300s. Their current patch goes from the console to DMX 3 on the patch bay, to the stage, daisy chained through the movers, back to the stage, back to the booths patch panel, and from the output of DMX 3 to the input of DMX 1 to the dimmer rack. Somehow running all this before sending the Ion's signal to the dimmers stops the lights from reacting. We do not know, however, what specifically helped in this process.

We do not have more time in the theatre tonight to troubleshoot more but tomorrow night we hope to spend much more time testing the DMX run and other options as well as call tech support. If you have any more information or suggestions on tests to make please let me know!

 

Thank you so much for all your help.

That is a heck of a long path for the DMX.  Not knowing the Clay Paky's it might be that they are re-generating the signal, but I suspect not.  That being said, a long run of DMX can sometimes tame some signal goofiness.  It can sometimes also make it more present, as can either terminating or not terminating the DMX runs.  But that is not the issue here.

So if I understand your situation correctly, if you plug the ION directly in to DMX 1 to the dimmers, you get a slow pulsing.  When you make the cable path run from the booth to the stage, through 2 more devices (the clay pakys,) and back to the booth, then on to the C21 processor, the problem seems to get better?

Do you know if the DMX signal from DMX 1 lands directly on the dimmer rack DMX input?  Or does it pass through any other permanently wired devices in the chain (i.e. a VisionNet to DMX interface, a Premiere Architectural processor, or some other control system for the houselights?)

Is there a network setup for the Strand system for running Strand Shownet (sorry ETC I know it's your forum, but the problem I suspect is related to Strand configurations.)

If there is a network setup for the lighting, do you know if you have an N21 or SN110 nodes in the signal path?  If so, do those devices either receive DMX or send DMX to the dimmers on the same Strand NetSlots?  Depending on how the Strand Netslot rules are setup, you can have two devices on the network fighting for control (put the lights at 100, no put the lights at 0, no put the lights at 100,) causing a flashing problem that looks quite different from bad DMX or unterminated DMX. It isn't a reflection issue, but a fight for control.  This can usually be solved by giving each device listening to the DMX a different set of netslots.   An easy test is to disconnect the DMX wires from the C21 processor housing if you feel comfortable doing that, and letting the Shownet DMX node handle the console DMX input to the rack, all of this is provided you have a Strand Shownet network installed.   If you do have that, and disconnecting the rack DMX eliminates the slow pulsing, then I'd contact Strand Tech support in Dallas to pursue further remedies.  If not, then back to DMX terminations and wiring checks.

Another thought on the simpler DMX wiring checks, if you can take the patch panel plate in the booth off the wall  and check to see if both the Data - and Data + wires are landed on the connector terminations, that might be a good check.  I've seen the DMX wires come loose from these plates (both on ETC and Strand jobs,) when the wires either weren't inserted far enough into the pressure plates, or the screws weren't sufficiently tightened down.  This could give faulty DMX which is just solid enough for the rack to respond, but respond with the flickers you are seeing.  

Finally, as I don't know your skill level, please take this with the respect is being delivered with... If you need to open the dimmer panel or the patch panel plate, and there is 120VAC or higher present in that device (the dimmer will have that voltage available,) I highly recommend you shut the main power to that device down before opening up any panel.  This is meant to protect both the equipment, and more importantly, yourself from shock hazards.  If you don't feel capable or qualified to open up any of these panels, then by all means contact someone who is. 

 

Good luck.

 

Just curious if you have had any further luck with your dimming problem, and if a solution was found, what it was?

 

Hope you have your problem resolved. 

 

Sorry I have not responded in a while. We had a limited time to do tests in the theatre space. However we found a solution even if we have not found the problem. We have found that putting an opto splitter between the board and DMX 1 in the patch bay going to the dimmers stops the pulsing. We also tried a few other things to see if we could isolate the problem before we got to this. Below is the list of things we tried. We also made a terminator only to find out there is no out for DMX and that it is hardwired into the dimmers. This leads me to think that there has to be a self termination in the processor's settings but the technical of the theatre I spoke to said it is really complicated and wonky to get through the settings to check if it is terminated. 

 

Findings (in order of path)
console- DMX 3- DMX 1 = good
console-DMX repeater opto splitter- DMX 1 = good
console- ground lift 5'+15' dmx cable- DMX 1=small pulse/chase with control on intensity (basically ground lift doesnt work)
console-100ft grey dmx- DMX 1 = bright erratic flash with no control, automatically turns on when dmx is connected
console-100ft black dmx-DMX 1 = all ON at full when DMX is connected
console- black plus grey (200ft) = only control over FOH channels when all channels captured, all other channels at full

It does seem like you are running into an unterminated DMX connection in the dimmer rack, and/or a mis-wired DMX cable. That is one weird set of scenarios you presented with the various paths of DMX.

If I recall correctly, it is just a jumper or dipswitch on the processors central interconnect console (CIC)board near the terminal block for the DMX wires, and should be fairly easy to change.   Strand Tech support should also be able to tell you where it is located. I would strongly suggest the rack be shut down completely before removing the processor tray out to check this, as the only way to safely open a dimmer panel is to have it shut off. 

Good Luck.

I installed the c21 processor upgrade in a Strand CD 80 rack.  I then purchased a GiO.  I was having the same issue.  I installed a pathport node in the line and everything worked like a champ. I apparently needed to translate ETC dmx to the way that the strand racks understood dmx.

I ended up with this solution from Vincent Lighting in Cleveland, Ohio.  

These kind of issues really only can be one of two problems.  There could be an electrical signal issue such as a ground loop,  missing common reference, missing D+ or D-, or missing termination.  The other option is a data rate issue due to the C21 upgrade not able to understand the DMX timing from the Gio.  In either case, note that the Pathway node will change both the electrical properties by providing a new ground reference [or floating it depending o installation] and by changing DMX timing.

My first suggestion, based on my experience with C21 processing, is to change the DMX output rate in the Gio to either Medium or Slow to see if the problem goes away.  I'm more of a dimmer and data guy than a cosnole guy so I might have this next step wrong.  Exit to the shell on the Gio and change the speed there and then go back into the Gio program.

Let us know how that works.

David

Turn off RDM. If what you're controlling is "unknown", I've found that some older electronics do not know what to do with the RDM signal. I've had LED tape pulse due to the controllers being junk.