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Need advice on tracing /testing DMX lines

Discussion in 'Lighting and Electrics' started by Ravenbar, Mar 10, 2019.

  1. Ravenbar

    Ravenbar Member

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    Working at a HS I work at once a year for their spring musical. After asking for several years, and them needing them for architect, the schematics have been dug up for the lighting system.

    The last few years, we've finally been getting a few DMX controlled fixtures/toys. When the place was wired(in 2008), they installed DMX output ports on the raceways, as well as constant power plugs for DMX controlled fixtures. Last year I tried to connect to those ports and was receiving no signal, as far as I could tell. Assumption was they were never hooked up. In the end, I and a dedicated cable back to the board and used an antique Colortran Status board to control the fixtures. Last year tee toys were a couple Chauvet Abyss USB's and a pair of RGB LED pars. This year, so far all I'll be controlling it a 4 channel dimmer pack running led strips in the front of a 4 step staircase.

    Now that I've got the blueprints from when the system was installed, I opened the splitter box and all the wires for the raceway DMX outputs are connected. Traced the wires up and they do connect to the raceways.

    Got home tonight and I made up a DMX line tester with a XLR plug and and LED/resistor so that's the first thing I'll be checking next week(not ruling out operator error on if there's signal to the port or not). Where else should I look? I don't see a terminator on any of the lines, as I suspected might be the issue.

    System consists of a ETC Expression 3, feeding an 8-way pathways edin 8-way splitter(5 connectiuons used per blueprints and visual inspection, 2 feeding dimmer racks and others feeding raceways), and (2) sensor dimmer racks with a total of 120(96 + 24) dimmers.
     
    Last edited: Mar 10, 2019
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  2. SteveB

    SteveB Well-Known Member

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  3. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @Ravenbar Goddard Mini-DMX'ter; worth it's weight in your favorite hallucinogen (Essentially the original though many have followed their lead). . .
    Toodleoo!
    Ron Hebbard
     
  4. Ravenbar

    Ravenbar Member

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    The Doug Fleenor on is pretty much what I've built, although it only has one LED as I had issues building it as described from online research and connecting LED's to both data lines and connecting the other legs together, without ground, lead to both LED's on with no ground.

    Trying to keep this on the cheap as this is the only show I do and I barely break even as far as pay goes on a good year.
     
  5. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    On the back of the Exp3, are there cables to DMX1, DMX2, & DMX3? Start by testing your newly-made DMX TSTR in the Expression, then move to the splitter, DMX . Then to the raceway s.

    A DMX line, or "branch" only requires termination when it is used at the last device. Splitter outputs, and live but unused lines, don't need a terminator.

    I hope this is the recipe you followed: http://www.bigclive.com/dmxtest.htm .
     
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  6. Ravenbar

    Ravenbar Member

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    I've already tester my new tester on my USB-DMX dongle and it seems to work.

    I'm planning on working my way our from the board, although directly testing the splitter output is nearly impossible as it's hard wired terminal strips.

    Board outputs to DMX1 and DMX2. DMX3 is empty.

    My thinking regarding a terminator, since prior to looking at the blueprints(and knowing there was a splitter), was that the dimmer racks and such were daisy chained together, with a pass through jumper connection somewhere with a terminator on the out, prior to the wiring going to the raceways.

    Didn't know unused lines/splitter outputs didn't need terminators. My education was limited to conventional fixtures and a few color scrollers. Make my living now sorting recycling so I'm not up to date on much.
     
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  7. Ben Stiegler

    Ben Stiegler Active Member

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    Possibly, your splitter is defective. I suggest bypassing the active splitter by connecting the board DMX one or two output directly to one leg of where the splitter outputs go. See if you have operational lighting on that leg. Proceed to test each post splitter leg one at a time. If those work then take a closer look at whether the splitter is operating properly .

    PS you should talk to the facility about billing them separately for diagnosing and maintaining their equipment outside of what you get paid for doing the show. I have usually been successful when approaching venue management after discovering a problem like this
     
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  8. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    The expression 3 also can adjust Outputs on the console. So you will want to look at that as well.

    If it’s not a true 1 to 1 then you might be looking at a split address setup.
     
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  9. Ravenbar

    Ravenbar Member

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    I'll definately look into the splitter being defective is other options fail.

    As far as billing them, I treat it as a volunteer job. They give me a little directly from the show, then I send an invoice to the school for lighting maintanence for a fixed amount after the show. Essentially, I'm already set up the way you recommend, although I don't treat it as such. Also, the main reason for finding the blueprints for the install were for a system upgrade/overhaul, so any repairs will be temporary.

    Patch is set 1 to 1. I ran into an issue on my troubleshooting this past weekend. Board is limited to 400 Channels. Patch is setup so universes 1, 2, and 3 are all start with channel 1(i.e. ch1, 513, and 1025 are ch 1), and they go up sequentially.

    My iussue was that, inmy not knowing the console was limited to 400 ch, I attempted to change channel could to 500. Wasn't watching the screen and set it to 005 ch., which in effect reset the patch to blank. Didn't realize what happened so I had to hook up my laptop DMX converter to the dimmers and power up lights so the set crew could have lights to work, While I figures out what happened/fixed it.

    Main goal for this whole thing is so we don't have to rely on my homebrew USB-DMX converters and old clunky laptop to run the toys when we have the facilities in place so we should be able to run them off the house light board.
     
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  10. ETCFIELDENG

    ETCFIELDENG Lin Wheeler ETC, Inc.

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    Hi Ravenbar, Could you please email me the Job# and name of your site? Or a scan or photo of the control riser. Thanks, Lin Wheeler ETC.
     
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  11. Ravenbar

    Ravenbar Member

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    Job name I recall was Madrid-Waddington CSD and install date was summer 2008. Not sure of the job number.

    I'll shoot an email off to the show director. Otherwise I won't be able to get it until this weekend. Thanks.
     
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  12. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    The expression 3 is more than capable to do it.

    You might have 400 psychical channels but you have 3 “universes” that you could patch to.

    So addresses from U2 into channel 300 or whatever you want.

    The real issue you will have is when you want to profile the moving lights. You will need some floppy’s and the PE.
     
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  13. Ravenbar

    Ravenbar Member

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    Got that.

    Not moving lights being used so no worries there. This time around I'm looking to control a small 4ch dimmer pack, controlling so LED strips in a set of stairs. Need 4 circuits there for control and only have 3 available through the house.
     
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  14. Ravenbar

    Ravenbar Member

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    In addition to my previous response, I just thought of another reason using multiple universes will get complicated quickly. I'm working with people who barely understand how any of this work using 1 universe. Most years the shows lighting is controlled via the 24 submasters on the board as that's something they understand.
     
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  15. Ravenbar

    Ravenbar Member

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    Finally figured out the problem today.

    IT was in the way the outputs from the board were configured. Port 1 was set to start at start at 1, port 2 at 513, and so on. The dimmer rack is, I'm guessing, hooked to output 1 and the splitter to output 2. Even though the patch was set to duplicate ch 1 to 513 and so on, the light not being addressed to 513 meant no workie. I reset the output so all outputs start at ch 1 and everything seems to work now.
     
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  16. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    Ummm. You want the ports separated. Having them all addressed at 1 is a nono. Also surprised the board even let you do that.

    The fixture address or dimmer that you are going to use would reflect the second universe. 513=1 on the dimmer/fixture address coming outta port 2.

    Nothing in DMX goes past 512.

    Essentially now you just double patched your board. So when you bring up Channel x then dimmer x1 and y1 will also Fire.

    You might want to brush up on DMX 101. There is a ton of videos and articles to explain all of it.
     
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  17. Ravenbar

    Ravenbar Member

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    Any video's you recommend? Although I have an college degreee in this stuff, my education was lacking on the modern stuff(limited to conventionals(early Altman 360q era and a handful of scrollers). Newest fixture we had as a handful of S4 Jr. in one of our secondary space. The college primarily had an acting program and added on a design/tech degree, which is what I got. This is the only show I've done for the past 6ish years. Board is an ETC Expression 3, so no where near current technology.

    That's not going to have a double patch issue. House system had 120(10 or so are for the Unison house light system) dimmers(board has 400 channels). Max addresses bing used well within 1 universe. Addressing the additional fixtures starting at 125. No crossover of address is going to happen as no address will exceed 512. Currently set up to use 4, although I may use 12. I've got a 4ch dimmer pack set up right now, although I'm considering the purchase of a DMX-LED strip light controller. The most the school employee's know is how submasters work and the basics of how to program them. I get pushback when I even attempt to program cues for shows.

    Plan is independently controlled lighting on the front of 4 steps(show director is ordering that so I'm not sure how many channels will be needed, discussion has be for amber LED's but I'm not sure if we're ordering amber LED's or I'm going to mix anber from RGB LED's). Only 3 circuits available on the front of stage so utilizing the additional dimmer pack free's up 2 channels, if I use one circuit to power the dimmer pack(I know it's not good to provide constant power via a dimmer, but it's what I've got. All of the non-dimmer power on the front of stage is on 1 circuit(not via the dimmer system), and the orchestra has been known to push capacity of that system. Adding an additional 20a draw is a recipe for disaster.

    I'd rather go about it this way rather than messing with the patch as its simpler and it works. At the end of every show, I wipe the board and program a simple house plot for the school year.
     
    Last edited: Mar 16, 2019 at 5:52 PM
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  18. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    You can google DMX 101 and t will spit out enough reading material and videos to last you a while.

    If you are only using 1 universe then you should just make everything come out of Port 1. So Port 1 to opto and then branch out from there. Because if later down the road someone tried to use the board and sets a fixture to address 1 on universe 2 then channel 1 on the board is going to control dimmer 1 and fixture channel 1 of the fixture.

    So I reiterate that you really shouldn’t have all ports start at 1.

    The Expression 3 is a nice starter board to learn the basics on. Bust out the 700+ page manual and grab your drink of choice and go to town.

    College should of taught you the basics on these things especially if you got a degree in it. If not I am sorry. Not to be condescending just genuinely sorry it didn’t get taught to you.
     
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  19. Ravenbar

    Ravenbar Member

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    Ideally, if I could get everything to come out of port 1 I would. I've had no luck getting that to work. Reading the schematics, it appears everything comes out of 1 port to the splitter, then branches out. If that was the case, I'd never have run into these issues. The paperwork wasn't available today for me to review(school currently looking to do an upgrade so director(person who deals with lighting for most of the year/superintendents wife) had the paperwork to make a copy. The system, in practice, seems to be set up so output 1 goes to the dimmer racks and output 2 goes to the splitter. I'd tried setting the fixture to channel 1 and bringing up ch 1(Ch 513 is patched to ch1), and got nothing.

    As I said in my previous post, at the end of every show I reset everything to zero and reprogram an base plot. No one there has any idea that a universe 2 exists and has no interest in learning about it. All they care about is that the lights work(which is why one of my main jobs every year is fixing burned out/broken lights).

    As far as the Expression 3 being a good board to learn on, I originally learned on an ETC Express 24/48, and an Expression 1. The Expression 1 ended up in my personal possession when I left the college((repeat broken grandmaster fader, and they were throwing it away), a problem which seems to have fixed itself in 10 years sitting in the garage). I'm well acquainted with the manual. Graduated in 2008. Had a fellow student a year or 2 prior write a scathing review of the college for this exact, out of date reason. I spend most of the year standing in front of a conveyor sorting garbage(recyclables). Not really able to keep up to date on the new stuff.

    What it basically boils down to is to control I have the option of a homebrew USB-DMX dongle using free software on an older laptop, using a Colortran Status 24/48(in addition to the Expression 3, which is what happened last year) or, using this less than ideal solution which(everyone involved understands) if it works as it seems it should, no one will be the wiser. I'd rather have a non-kosher solution that works rather than a kosher solution that doesn't).
     
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  20. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Never say never. I've done it. Having all the ports start at 001 just means you're using the desk as (or in lieu of) an opto-splitter. Not a problem until or unless @Ravenbar needs to control more than 512 addresses.
     
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