Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14

Thread: DMX resources

  1. #11
    Join Date
    Aug 2013
    Posts
    73

    Default

    Quote Originally Posted by absolom7691 View Post
    Curious about why optocouplers are discouraged. Are they not fast enough?
    They're plenty fast for DMX (only 250kbaud), that's not the issue. Just not an appealing solution these days, generally. One 14-pin digital isolator can replace four optocouplers and a handful of resistors, less board space and maybe cheaper.

    There are some all-in-one solutions for power+data isolation, including parts that have an entire isolated DC-DC converter, signal isolation, and RS485 transceiver in one PCB-mount module. There are also some general-purpose isolator ICs that have a built-in DC-DC controller and just need an external transformer. I tend not to use those personally just because they tend to be single-source parts, so you can find yourself in a bind if they go out of stock when you need them.

    Really the only advantage to optocouplers in my book is that they're easy to socket, so they can be replaced in the field if damaged, but if your isolated DMX port takes a big enough hit to fry the optocouplers how much else is gonna be toast? You can socket the transceiver IC as well, but I'd rather save the board space and parts cost and put that towards front-end protection. Transceiver ICs tend to be fairly robust, so you don't have to go crazy to protect them against the most likely fault conditions. Anything that goes beyond that, and, well, that's one of the reasons our DMX interface is a separate small PCB

    Re: the other stuff, I tend to just spew information at the slightest provocation, but I'm happy to clarify anything if there's something I didn't communicate very well.

  2. #12
    Join Date
    Sep 2014
    Location
    Colorado USA
    Posts
    793

    Default

    Quote Originally Posted by absolom7691 View Post
    I found a pretty good resource here:

    https://www.element14.com/community/...g-applications
    Great DMX topic thread absolom and contained good DMX signal scope examples. I've read about DMX over the years, bought Arduino's and stuff to play with making something to play with, but never got aroundtoit. All I could find were squaredoits.

    But this is re-inspiring. Thanks
    ________________________________
    Everything depends on everything else

  3. #13
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,489,446

    Default

    Quote Originally Posted by aberry View Post
    I tend to just spew information at the slightest provocation
    And we are all grateful that you're willing to do so, Andrew! That sort of participation is what keeps the forums alive.

    Adam

    PS: Right after I hit "Submit Reply" it occurred to me that the contributions of everyone in this thread are worthy of the same praise I heaped upon Andrew. It was not my intent to snub anyone else; these sorts of discussions are what set this forum apart from other laser discussion groups.

  4. #14
    Join Date
    May 2007
    Location
    1 hr from everything in SoCal
    Posts
    2,753

    Default

    Following what Adam said, thank you all for your responses! To those who are gladly willing to disseminate information, you are appreciated!!
    If you're the smartest person in the room, then you're in the wrong room.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •