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LOR Adaptor Burning Out

Discussion in 'LOR DC' started by pilbralights, Jun 7, 2016.

  1. pilbralights

    pilbralights Infected with CLAP

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    I did my first show last year with a few dramas (maybe a first year thing I hope). I burnt out 2 X LOR RS 485 adaptors and think it may be current flow getting back through the adaptor, 1 lasted about 2 weeks while the other one only a few days. All the control boards are DC each with its own Switch mode PSU 240V>24DC. I have a few questions: does the RS 485 have a ground reference??? then if so does the rs 485 at the control boards go the -VDC on the board??? do all - VDC have to be joined together to form a common??? and then does that common need a reference to earth??? should I install a isolated usb from the computer to the adaptor effectively isolated it from the PC's earth??? Sorry to fire all these questions around the place, any info would be great.
     
  2. David_AVD

    David_AVD Bite my shiny metal ass!

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    RS485 does indeed use a common reference conductor.

    It would be interesting to see what has failed in the LOR USB adapters. Do you mean they physically burned ?

    As for an isolated USB port/hub, they are a pretty rare thing and not a cheap item.

    I do make and sell an isolated USB-RS485/DMX adapter if that helps. The RS485 chip inside is socketed so you can easily replace it if do damage it.
     
  3. OP
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    pilbralights

    pilbralights Infected with CLAP

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    Thanks David,


    Yes please see photo, both adaptors failed in the same areas. I will keep that in mind, cheers


    I have also included the layout of the control boards and PSU.
     

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  4. David_AVD

    David_AVD Bite my shiny metal ass!

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    One way I can see that damage happening is if there is an issue with the mains earthing.

    There should be minimal voltage differential between the PC earth and the remote power earth points.

    If there is, I'd be seeking the advice of an electrician as you may have a nasty mains fault lurking.
     
  5. Ɠαяєтн

    Ɠαяєтн Mae gen i C.L.A.P ei heintus iawn

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    Where about in the Pilbara are you? I come to Karratha every 2 weeks and may be able to help.
     
  6. OP
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    pilbralights

    pilbralights Infected with CLAP

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    Hi Gareth, Paraburdoo mate, in the desert haha welcome to come over if you want, cheers for the offer
     
  7. David_AVD

    David_AVD Bite my shiny metal ass!

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    If it's super dry out there, maybe you do have an earthing issue.
     
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    pilbralights

    pilbralights Infected with CLAP

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    Thanks for the info guys much appreciated! Looks like I have a bit of testing to do. Isolated USB seems to be the go and better protect's everything anyways and more investigation is required, cheers again.
     
  9. David_AVD

    David_AVD Bite my shiny metal ass!

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    We have the isolated converters in stock. You'll also need an RJ45 pinout adapter to use it with your LOR system. You could make your own or we sell them for a measly $6.60 :)
     
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    pilbralights

    pilbralights Infected with CLAP

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    Ran 2016 show with the isolated USB and no dramas, the adaptor definitely had reference to ground through the adaptor then through the PC earth this caused small amount of current flow which damaged not only the adaptor but damaged 4 X LOR boards on the RS 485 side of things, very costly but at least I know now haha. I now have 2 of everything and a back up ;)
     

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