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    thirdsigma
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Smartfade ML and erratic intensity behavior

Hi,

I am using a Smartfade ML in a rented facility.  Last night, I patched all the dimmers in the building (there are only 48 of them) into the Smartfade as a simple 1:1 patch.  When I unplugged the DMX cable from the facility's console and plugged it into the Smartfade, some lights began to flicker.  It was almost as though someone was quickly wiggling the fader controlling the light.  I turned down the DMX output speed all the way to "slow" and the problem improved, but didn't completely go away.  In addition, I found that the control of many of the lights was erratic (i.e. I would move a fader and the light would jump to levels rather than smoothly transitioning)  Keep in mind that during this, I was slowly moving the fader all the way from 0 to 100% and back, so this is not an issue with the level being set elsewhere and the fader just grabbing control at a certain point.

 For the purposes of this test, all the lights are conventional fixtures (no intelligent lights).  The console that the facility owns (and which works just fine) is an ETC Express 24/48.  The dimmer panels say "Sterner" on them--I've never heard of such a company before.  The Smartfade ML is running v 2.0.1, and I have SmartSoft v 1.0.1  During the duration of this test, I had the Smartfade connected to my laptop via the USB connection.

Since the facility-owned console works fine, I am fairly certain that the problem is not with cabling, termination, or dimmers.  My only theory right now is that, perhaps, the USB connection between the laptop and the Smartfade was demanding too much of the Smartfade and the Smartfade was not keeping up with DMX updates.  I will test this theory next time I have access to that facility.

Does anyone else have any ideas as to what could cause this problem?  Are there any other parameters on the Smartfade that I could adjust to fix this?  Any adivce would be much appreciated.

Parents

  • Have you used the ML with anything prior to this?

     There processing power available is more than sufficient to handle USB and DMX at the same time, even at the highest speed setting.  It's more likely that there's a hardware problem.  Patching your dimmers to the other DMX output, or connecting the ML to a different DMX device will help narrow things down. 

    There's also a self test that checks the DMX hardware, but you need a cable with two XLR5 male connectors.  You can get into self test mode by holding down the menu/okay key while booting the console.  Press the menu/okay again to step through each test. The last test is a memory check and will erase anything you've entered into the console such as memories, pallettes, and patch.  To avoid this, you can unplug the console at any time during any self test and reboot.

  • in reply to MPenisten

    Thanks for your response.

    Yes, the Smartfade has been used to control some LED color mixing fixtures prior to this with no problems.  Those fixtures are patched to universe 1.  The fixtures with which I was having problems were all patched to universe 2, and this is the first time we've attempted to use universe 2 (supporting your theory of a hardware problem).  During my tests last night, we did not have the LED fixtures connected, so I don't know if the problem I was seeing was occurring on universe 1 as well.

    I will try playing around with my patch to see if I can isolate the source of the problem.  Perhaps there is something wrong with universe 2 on this consolse.

    I would also like to run the self-tests you mention.  Do you know the pinout of the XLR5 cable that I would need?

    Thanks again!

  • in reply to thirdsigma

    The DMX self-test squirts some data back-and-forth between the two ports so it can test both the receive and transmit parts of the DMX chip.

    You'll need a straight-thru 1:1 pinout cable, just with both connectors male instead of the usual male--to-female cable.

    It's sometimes called a "Gender-changer" cable - you can also get just an adapter as an XLR-5 barrel.

    It seems quite plausible that you've got a faulty DMX chip on Port 2 - if that's the case, then you can either do the swap yourself or ask your local dealer to do it for you. It's a fairly simple repair, but if the console is in warranty it's probably best to ask your dealer to do it!

Reply
  • in reply to thirdsigma

    The DMX self-test squirts some data back-and-forth between the two ports so it can test both the receive and transmit parts of the DMX chip.

    You'll need a straight-thru 1:1 pinout cable, just with both connectors male instead of the usual male--to-female cable.

    It's sometimes called a "Gender-changer" cable - you can also get just an adapter as an XLR-5 barrel.

    It seems quite plausible that you've got a faulty DMX chip on Port 2 - if that's the case, then you can either do the swap yourself or ask your local dealer to do it for you. It's a fairly simple repair, but if the console is in warranty it's probably best to ask your dealer to do it!

Children
  • in reply to Richard

    Hello,

    Before deciding that a DMX port is faulty it might be worth considering other possible explanations..  SmartFade does not have opto-isolated DMX outputs, in common with most smaller lighting boards.  When connected via USB there is a possible path to ground (depending on the computer and screen in use) that COULD cause a ground loop back to the fixtures.  If any of the fixtures or dimmers do not have opto-isolated inputs then you may well see pretty much exactly the fault you described.

    I do not recognise the brand of dimmers you were using.  Perhaps they do not have opto-isolated inputs.  If not then that could well expalin the faulty behaviour you  saw.

    Another possibility is a DMX wiring fault.  DMX has an annoying habit of nearly working all the time if one of the wires is broken.  Some combinations of transmitters/receivers can deal with this and some cannot.

    I personally suspect it is rather unlikely that the DMX output hardware on one port is faulty, but not so faulty as to be non-operational.  Usually if a driver chip dies it really does die.

    So, get some dimmers or devices (anything will do) and try running them 1st from port 1 and then from port 2.  If they run from both then I would say that DMX outputs are not the explanation.

    regards,

    Adam Bennette

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