Loss of dmx

AndreasAndreas Registered User
I'm currently running a show using the Hog3pc system (1 PC, 1 widget, 1 playbackwing and 1 progwing).

During the last show I ran into a very confusing problem. Suddenly all conventionel lights drops to zero (for about ½sec). Having no clue why? After a few minutes this happens again, although this time I spoted the widget during the blackout, and I saw that the two diods active and dmx OK were out but they came back as the lights went up again (I truly suspect a connection between the diods and the blackout:p )

Hence the link doid all the time indicated connection between the widget and my comuter (the widget is directly plugged in my computer) I'm clueless whats the fuzz is about! :1zhelp:

/ Andreas

Comments

  • Kris.gKris.g Registered User
    edited February 2007
    I am unfortunately unable to comment at all as to why this happened.
    However as a wee safety precaution for show conditions I would make sure my Dimmers are set to "Hold last DMX command"

    I am guessing because you have not mentioned your moving lights cutting out too and things like Pan and Tilt going to ZERO values that the Widget is not actually sending out all zeros on the DMX lines.

    As I said before........ this is not an answer to your problem, merly just a way of making sure you don;e have blackouts unexpectedly during a show.

    Kris.
  • Marty PostmaMarty Postma Registered User
    edited February 2007
    Are you running H2 or H3 PC?

    Have you checked to make sure your USB cable and connections are good?

    Is EVERY single other application that you can turn off disabled on your PC?
  • AndreasAndreas Registered User
    edited February 2007
    Thanks both Kris and Marty

    I'm runningthe Hog3, I belive my cables are good and the widget link diod indicated a connection all the time. And yes, every other application on my pc is turned off. I've ran hog2 on this pc for four years, but this was the first larger show with the hog3 on this computer, but I'v done all the programming on this pc and we were on the 20'th gig of the show when this problem occured.
    Unfortunately (or good) we had only 21 gigs to do and the problem nerver showed on the final gig, so I never got a chance to investigate the mysterious dissappearing of the dmx further...

    / Andreas
  • cmuenchowcmuenchow Registered User, Administrator, HES Staff
    edited February 2007
    Is it possible that you had done a garbage collect at the time of this drop out?
  • AndreasAndreas Registered User
    edited February 2007
    Nope, no garbage collect, I'm afraid to say that there were no fiddling done at the time of the drop out, the tech (me) was sitting with his arms crossed and enjoyed the static look on the stage and had done so for aprox. 5 min before the evil blackout occurred...
  • teericksonteerickson Registered User, HES Alumni
    edited February 2007
    Andreas,

    Did you have any other fixtures on the same universe as the dimmers?
    If you had moving lights on the same universe and they didn't close their shutters and move to pan and tilt of 0/0, then this was either an issue with your dimmer rack or possibly an issue with your dimmer rack being particularly picky about DMX timing information.
  • AndreasAndreas Registered User
    edited February 2007
    Yes, I had both moving lights, scrollers and dimmers on the same universe. But the phenomenon of the drop out were the same as if I pulled the dmx cable: All dimmerch. went to zero and the movings and the scrollers kept their last positions, its the same thing as when I close my hogpc application with faders still up: all dimmers go down but moving and scrollers remain at their given position.

    Also I noticed that the indicators on the widget for "active" and "dmx ok" dropped too...

    Therefor I feel quiet confident about the problem is located to either my pc or in the hogpc application.

    / Best,
    Andreas
  • AndreasAndreas Registered User
    edited February 2007
    I spotted another thread with an issue that is remarkably close to my experience...:confused:



    http://forums.highend.com/showthread.php?t=3409
  • teericksonteerickson Registered User, HES Alumni
    edited February 2007
    Well, if the movers didn't change positions then we know that we didn't clear the DMX buffer and send out all 0s, which is a good thing. It's possible that either we briefly stopped sending briefly or that the refresh rate changed enough that the dimmers got upset. It's going to be tough to know without actually taking a look at things with a DMX analyzer. I'll see if I can reproduce this in our test lab. If you'd like to send me your show file I can see if there's anything odd there that may have contributed to the problem.

    Thanks.
  • garygary Registered User
    edited May 2007
    i have found that if i dont have a opto splitter in the rig and use a terminator at the end of the line it tends to drop the dmx out on the ipc. maybe Tom could shed some light on this.
  • teericksonteerickson Registered User, HES Alumni
    edited May 2007
    Gary,

    I've never seen the problem you describe.

    Are you sure that your terminator is built correctly?
    What is the total length of your DMX run?
    How many fixtures do you have on the run?
    What type of fixtures are they?
    When you say that it "drops the dmx", do any of the fixtures work, or will they all timeout because they've lost DMX?
  • garygary Registered User
    edited May 2007
    what happens is i have a FOH cable 100mt then if i go into the dimmer rack 6 x jands hp12's it works fine, if i terminat the last dimmer it makes te lights do random things eg: strobe
    the terminator is on board the dimmer.
    this set up only happens when i dont bring the splitter.
    most of the time i have the splitter after the FOH cable then splitting into the dimmers. this only happens with the hog ipc.
    even in other setups if i run a terminator, ether onboard or a resister type, and no splitter it messes with the data even if the cable runs are short.
  • teericksonteerickson Registered User, HES Alumni
    edited May 2007
    Gary,

    Do you have an external terminator that you could try using?
    I'd be curious to know if you see the same results.
  • dslodkidslodki Registered User
    edited May 2007
    Hmm. Strobing dimmers? The feared "disco effect"? I've had these same troubles many times with Strand CD80 20Kw dimmers and 6x12 CD packs, as have several of my colleagues. And I have noticed it ocurring in terminated lines and disappearing without the terminators. Now, after much consultation with other programmers and manufacturers apparently there are some problems with newer consoles and older dimmers and that's got to do with newer consoles (Hog3) having something different (refresh rate? evolution of DMX protocol? weird bogeys? who knows) that makes those older dimmers strobe. First, let me say that nobody has ever given me a definitive, "this is what's wrong" type of answer. And DEFINITELY NOT a "this is how to fix it" type of answer. But the problem, especially with the 20Kw dimmers is so pervasive that it occurs nearly every time with at least one of them. (Love to see those boat anchors on the order, lemme tell ya.) And since there is not another company on the planet that makes DMX controlled 20K dimmers, we're screwed. But enough about me. All I'm saying is that the "disco effect" is thought to be related to older dimmers used with newer consoles, and counterintuitively is not thought to be related to termination. If there's anyone who can expand this conversation to definitively solve the problem, by all means bring it on.
  • eboxereboxer Registered User
    edited May 2007
    Now that you mention CD80s . . .

    One of our smaller theatres is run off CD80's . . . in AMX . . . we use an Insight (before that was a n inovator) but regarless, we do everyonce in a while experience the "drop out". Im wondering if for us that may be caused due to the DMX-AMX converter . . .

    Just for fun when i get back to school I'll put the hog or hogpc on the system to see if it makes a difference . . .
  • Fredrik WiggenFredrik Wiggen Registered User
    edited June 2007
    I have experienced "strobing dimmers" myself. I found the cause to be a faulty DMX cable in the fixture chain.

    I have also experienced "Para-normal" black outs of the conventional lights for 0.5s, like Andreas describes. This happened at a festival in the farm fields of Norway at exactly 6pm every day. It only lasted for a fraction of a second, non there less still frustrating. In my case I had been sloppy, and I found an earth potential between the Hog III and the DMX splitter unit. As soon as I got these two units on the same power source, the problem disappeared. Regarding the 6 o'clock issue, that was caused by the next door farmer starting up his hay dryers.

    fred
Sign In or Register to comment.