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  1. #21
    Jazz, I'm not sure to understand what you are saying... will the ESS fix the issue IF it is a ground loop going to the PC ?

    I have tried getting rid of the ribbon cable. Same problem, though I had disconnected the X axis motors because I didn't want to twist the gantry. But then it was a little more difficult to hear the noise but it was still there. I will do some more tests on Thursday, I'll connect everything back together to get the maximum noise, then disconnect the DB25 cable and see if that stops it. I'll let you guys know ASAP.

  2. #22
    Any ethernet socket is galvanically isolated on both sides. So it will not pass direct currently to and from the computer. The ground loop will then not be present. But if there is an issue in the wiring then it may cause issues nonetheless.
    https://emvioeng.com
    Machine tools and 3D printing supplies. Expanding constantly.

  3. #23
    Yes, but the ground loop could still flow through the cable from the BOB to the ESS, or not ?
    Last edited by eurikain; 07-03-2016 at 04:42 PM.

  4. #24
    It should not really unless the optos on the BOB are buggered or there is an issue on the board.
    Last edited by komatias; 07-03-2016 at 04:38 PM.
    https://emvioeng.com
    Machine tools and 3D printing supplies. Expanding constantly.

  5. #25
    It looks like the board only has optos on the input signals though. But as you said, there are so many cases of people using this BOB without problem that we can't just assume it's the BOB that's the problem ^^.
    Last edited by eurikain; 07-03-2016 at 05:07 PM.

  6. #26
    But then it was a little more difficult to hear the noise but it was still there
    What is noise you are hearing? You can't hear EMF
    ..Clive
    The more you know, The better you know, How little you know

  7. #27
    Quote Originally Posted by eurikain View Post
    Jazz, I'm not sure to understand what you are saying... will the ESS fix the issue IF it is a ground loop going to the PC ?

    I have tried getting rid of the ribbon cable. Same problem, though I had disconnected the X axis motors because I didn't want to twist the gantry. But then it was a little more difficult to hear the noise but it was still there. I will do some more tests on Thursday, I'll connect everything back together to get the maximum noise, then disconnect the DB25 cable and see if that stops it. I'll let you guys know ASAP.
    In theory yes it should but like been said depends if this really is the source of trouble.? That said I'd still change the BOB because it's clearly not very good because shouldn't happen even with parallel port.

    Now like Clive ask's What Noise.?

    I think you miss under stand what is meant by Noise. It's not audible so if your hearing any noise that's something else.?
    If your using AM Digital drives then I suspect it's because you haven't tuned them. Or what your hearing is the current reduction in the drive working while motors are stood still. This will make an Hissing sound.

    Electrical noise or EMF is a Silent Killer.!!

    Very difficult to help from distance when it comes to noise. All you can do is be meticulous with wiring and gnding. Ensure separation between signal and power cables.
    If still present then fit EMF Filters etc.

    If still present then start back tracking.

  8. #28
    I was helping (well trying) to help Geoffroy over the weekend with his "noise" issue. His current problem is that when he runs the spindle all the steppers start making random moves. It is these rapid random stepper moves that is the noise he is hearing.
    We started looking into the shielding of the spindle cable and he managed to improved it, but no change to the random stepper movements. He then removed the VFD unit and all VFD wiring from his control cabinet -still the same issue. So it does not look like it is caused by the cable radiating noise into the BOB.
    The last thing we tried was to disconnect the parallel port cable from the BOB. This did seem to stop the steppers from moving when the VFD was run.
    The reason I suggested he disconnected his slaved X axis motors was when the spindle was run these motors were sometimes going in opposite directions causing his gantry to twist. Removing them kept his machine safe, but did lower the "noise" from the steppers.
    It looks like the BOB is seeing noise on the signals from the PC when the spindle is run, which is then being used to send random STEP and DIR pulses to the stepper drivers. This could be caused by an earth loop between PC and control cabinet or by a poor 0v connection between the two. More testing will be required to find out which.
    Hope that clears up the meaning of the "noise", any suggestions welcome as to how to solve this one.

  9. #29
    Thanks Graeme, you couldn't explain it better :)

  10. #30
    You may well have a ground loop, however you would do well to relocate your BoB so that the PP cable from the computer plugs directly into it (get rid of the unshielded flat form cable).

    A good principle to follow when wiring up a cabinet is to put signal cables on one side of the cabinet and power cables on the other.

    Cheers,

    Rob
    Albert Einstein may have been a genius, but his brother Frank, was a monster

    Sent from my clunky old Windows 7 Machine

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