DMX noob.

Discussion in 'Miscellaneous [BG]' started by RitchS, Jun 7, 2019.

  1. Ok. I have spent some serious money on lighting and our lighting guy isn’t always available. I’d like to really get to understand DMX but...

    I. Just. Don’t. Get. It. I feel like I’m the only guy in the world who can’t figure this stuff out.

    Can someone please explain, in layman’s terms to a dolt like myself how I can make my Chauvet Gigbars and my Chauvet spot6’s and my Chauvet color strips to work with my Chauvet FootC DMX controller? Please? Pretty please?
    WI Short Scaler likes this.
  2. SteveCS


    Nov 19, 2014
    Hampshire, UK
    It looks like the FootC can only go to 6 fixtures at up to 6 channels each, so you might not have enough capability for the level of control I think you are looking for - you have 11 fixtures and the gigbar takes up 23 channels if you want to control each fixture independently. The 6Spot is 6 fixtures and needs 8 Channels, so again is beyond the capabilities of the FootC. It looks like the start addresses of the fixtures in the FootC are fixed, and it looks like the fixture addresses of the lights you have cannot be set individually, only the start sddress of fixture 1.
    For example, in 23Ch mode, the first PAR can uses Ch1-5. The second starts (and is fixed) at Ch6. The FootC has a fixed assignment of Ch7 to the second fixture, but to correctly address PAR2 this needs to be either 6 in the FootC or 7 in the gigbar. Neither of these changes is possible. The result would be that adjusting channel 6 of fixture 1 in the FootC would actually change the Red value if fixture 2 in the gigbar!
    I think you need a more flexible controller.
    Brad Maestas likes this.
  3. I have an ADJ controller that is Very flexible, but it requires a lighting guy behind it. I was hoping to make simple scene changes with the FootC.

    My issue is not understanding how to program or address these things. I need that “ahah!” Moment where DMX all makes sense.
  4. DirtDog


    Jun 7, 2002
    The Deep North
    When I get a minute later today I’ll post a link to a video that completely de-mystified DMX for me. It’s certainly not intuitive for a beginner.
    SteveCS likes this.
  5. Thank you very much D Dog! I hate feeling so mystified by something that everyone else seems to understand!
  6. DirtDog


    Jun 7, 2002
    The Deep North
    Here you go! I went through this journey a couple of years ago. I originally bought a controller that in no way could control my fixtures! It's not just all plug and play, even if you buy the same brand. My guess is your foot switch controller doesn't have enough channels to accommodate your fixtures (foot switch is I believe 3 channel, your fixtures are likely 7 channel). Worst case scenario for you is you need to invest in something like the Obey 40.

    If I don't use my system for a while, it's not unlikely that I will have forgotten what I taught myself. Double that for systems I'm unfamiliar with. I pull out my lights maybe 2-3 times a year.

    Edit: re: channels, what @SteveCS said....

    Brad Maestas likes this.
  7. SteveCS


    Nov 19, 2014
    Hampshire, UK
    I looked into that yesterday, and the 40 does not have sufficient channels per fixture. The GigBar uses 23 channels, so the Obey 70, with up to 32 channels per fixture, would be the one to go for.

    Even the ADJ 'Operator' only goes to 16. I say only, but actually that is fine for most professional or installed systems where each light is a fixture. The problem with consumer lights like the gigbars is they are multiple fixtures with little configurability.

    Thanks for the mention!
    DirtDog likes this.
  8. JohnMCA72


    Feb 4, 2009
    I'll try:

    DMX is a communication protocol that is divided up into 512 channels. Each channel contains a number from 0-255. The controller (i.e. FootC) sends the value of each channel down the DMX link. Each actual fixture pulls out the values that are intended for it, ignoring those that don't.

    Fixtures have a starting address, and use some number of channels to control them. Each fixture needs to be configured with a starting channel number (address). However many channels that fixture uses are contiguous from the starting address. To use your equipment as examples:

    The FootC controller can transmit 36 of the 512 defined channels. It breaks these up into 6 groups of 6 channels each, which it defines as a "fixture", although this has no actual relationship to what is actually attached to the DMX chain. to the FootC, "Fixture 1" is channels 1-6, "Fixture 2" is channels 7-12, "Fixture 3" is channels 13-18, "Fixture 4" is channels 19-24, "Fixture 5" is channels 25-30, and "Fixture 6" is channels 30-36. The FootC has no way of telling what is actually out there, all it has is its predefined grouping of 6 "virtual" fixtures, with 6 channels each.

    Gigbars can be configured to use 3-, 6-, or 17-channel modes ("personalities"). 17-channel mode gives you the most options, but uses most channels. It would eat up 3 of your 6 "Fixtures" on the FootC to control Gigbars in 17-channel mode ("Fixture 1" would control channels 1-6, "Fixture 2" would control channels 7-12, and "Fixture 3" would control channels 12-17, with channel 18 left over, unused.

    The 6-channel mode would allow you to have a 1-to-1 mapping between FootC "Fixtures" and actual fixtures. If you want to run 2 Gigbars separately in 6-channel mode, you could configure one of them with DMX address 1, and the other with DMX address 7. "Fixture 1" on the FootC would control what one Gigbar does (as defined in the Gigbar manual) and "Fixture 2" on the FootC would control what the other Gigbar does. If it works for what you want to do, you could configure both Gigbars with the same address (1, for example) and each would do the exact same thing, as defined in the FootC for "Figure 1". You can have any number of fixtures with the same address. There won't be any conflict, just multiple fixtures doing the exact same thing (assuming that they are all the same make & model, configured the same way, so that whatever the controller sends to that address is received by both of them.

    In 6-channel mode, the first 3 channels are red, green, and blue respectively, which provides your color mix. Channel 4 is the "master fader", which needs to be up at least somewhat if you're going to see whatever color is defined by the combination of channels 1-3. Channel 5 defines how fast, and in which direction, the Moonflower turns. Channel 6 controls the strobe rate. In 6-chnnel mode you can't control individual units (PARs & Moonflowers) separately, which is a disadvantage. 17-channel mode allows you to control each unit separately, but uses up 3 "Fixtures" in the FootC. It also complicates the programming, since you have to select & set channels 1-6 as "Fixture 1", de-select "Fixture 1" & select "Fixture 2" to set channels 7-12, then de-select "Fixture 2" & select "Fixture" 3 to set channels 13-17 (channel 18 isn't used).

    The 6Spot uses 8 channels, with channels 1-6 setting the colors for the individual pods. Channel 7 sets the strobe rate, and channel 8 selects one of the predefined macro sequences. Here, you're stuck having to use 2 virtual 6-channel "Fixtures" in the FootC, since the 6Spot doesn't have an alternative mode. If you set a 6Spot as Channel 19 as it's "base" address, it will use channels 19-26, eating up 2 virtual 6-channel "Fixtures" in the FootC (all 6 channels of "Fixture 3", plus the first 2 channels of "Fixture 4". Again, you're stuck having to set the 1st 6 channels of a 6Spot in 1 "Fixture", and the other 2 channels in another virtual "Fixture" in the FootC. The good news it that you'll probably be mostly changing colors, not strobe rates or macros, so it isn't as big an issue as 17-channel mode on a Gigbar.

    You might set both Gigbars to 17-channel mode (first 3 virtual "Fixtures" in the FootC), set to DMX address 1 and both 6Spots set to address 19, which will allow you to control everything on the Gigbars with "Fixtures" 1-3, and both 6Spots with "Fixtures" 4 & 5. Each Gigbar will do exactly same thing as the other, and likewise each 6Spot will do the same as the other. This may very well work for you.

    DMX lighting control is all about creating Scenes and Chases. Programming Scenes and Chases is done in advance, and you "run" Scenes and/or Chases for the show. A Scene is static, and consists of a particular combination of fixtures doing whatever. You program Scenes by selecting fixtures, adjusting their channels to do whatever color mix and intensity you want (limited by what the actual Fixture can do), and saving the combination into a Scene definition in the controller. Multiple Scenes can be defined. At showtime, you can call up Scenes and the lights will do whatever was defined in those Scenes.

    Chases are collections of individual Scenes. Once Scenes are built, you can add them to Chases. When a Chase is executed, it runs through its collection of Scenes, at a rate set by the controller.
    DirtDog, Brad Maestas and Wasnex like this.
  9. Rib 13

    Rib 13 Supporting Member

    Jun 20, 2006
    So, basically what you're saying is: Everytime you try to work with your DMX, you're telling it, "Ya'll gonna make me lose my mind....up in here, up in here"
    WI Short Scaler likes this.
  10. Brad Maestas

    Brad Maestas Sono est omnia Gold Supporting Member

    Nov 26, 2003
    Petaluma, CA, USA
    This is a big part of what I do at work. The one thing that really brought it home for me was understanding DMX addressing and how it's tied to the color capabilities of the instruments you are using. An RGB instrument uses 3 addresses. An RGBA/RGBI instrument uses 4 addresses, etc. This directly affects how many instruments you are able to accommodate with a particular controller due to its channel capacity.

    Analog boards are much more limited compared to digital boards. My technicians regularly use a Jands Stage CL digital board. It can control both incandescents (Leko/PAR) and LEDs over DMX. Another thing that I would highly recommend is having DMX terminators at the end of your signal flow. They essentially short the signal in a way that lets the controller know when an instrument is at the end of the configuration. This has solved many problems over the years. I use them on every show.
  11. Wasnex


    Dec 25, 2011

    Very thorough and informative.

    Here's something that probably won't help the OP, but it might be useful to someone else.

    With moving head type fixtures, consider what happens when you assign two instruments to the same DMX channels, but reverse the X axis on one instrument. On the old instruments I have used, this was achieved by adjusting dip switches that control the instrument's behavior. I believe on newer devices it will be buried in a digital menu and may be called Pan Reverse for the X axis control and Tilt Reverse for Y axis control.

    Now place the instrument with the normal X axis setting stage left, and the instrument with the reversed X axis stage right. Now when you tell the left instrument to move right towards the center of the stage, the right instrument will move left towards the center of the state. Remember the X axis is reversed on the right instrument, so it does the opposite of what the left instrument does across the X axis. But if you tell the instruments to move up or down, they both do the same thing. This makes it a bit easier to program multiple fixtures to do symmetrical synchronized motion.

    With a more advanced controller, you may be able to do this sort of thing with the actual controller, so you can have the symmetrical motion on one scene and then have them doing identical motion on the next.
    Brad Maestas likes this.