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Question Problem with interferences on servo with lighthouse

Discussion in 'Motor actuators and drivers' started by Bastiuscha, Feb 7, 2021.

  1. cfischer

    cfischer Active Member Gold Contributor

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    How did you install the ferrite core? also which one did you buy?
  2. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    @Bastiuscha - High frequencies make the square edges on the signals/pulses on the cables, or it’s RFI frequencies bleeding onto the signals from the control electronics, but either way it sounds like it’s your cables acting like antennas and radiating the interference. The ferrite would go on the cable nearest the electronics end if that’s what is generating the interference. Put it at the motor end and it will be much less effective unless there is circuitry there generating the interference. I don’t know if there is any problem with putting them at both ends if you have enough.

    Does the manual for the motion system say anything about grounding and did you do what they recommend? Grounds can often be reasons for RFI too but just checking boxes.

    Edit - Just was reading this (https://resources.altium.com/p/how-do-ferrite-beads-work-and-how-do-you-choose-right-one). It seems there’s lots of considerations to choosing the right ferrite and it’s easy to use the wrong one and not see a reduction in RFI. Maybe someone else knows the right ferrites to use.
    Last edited: Feb 14, 2021
  3. Bastiuscha

    Bastiuscha Active Member Gold Contributor

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    I buyed this Guy's. And installed exactly like the posted Video. Some small arround the individual Cables and the big one arround the complete Cable.

    Sorry, it looks ao like links are not working

    Attached Files:

    Last edited: Feb 14, 2021
  4. Bastiuscha

    Bastiuscha Active Member Gold Contributor

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    @Zed
    I installed the Ferrit's only on the Driver Side, like in the Video above. Sadly the only recomenndation is "change to a shielded cable".


    I tested a lot and i can say, the Problems already start with one Engine. Is here any Guy, who gets this Motors work with a Index? It lookes like a impossible Task. I'm shortly bevore order a G2 HMD. :/ If i play with Monitor i don't have any Problems. Seat ist working great.
  5. Bastiuscha

    Bastiuscha Active Member Gold Contributor

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    OK Friends!!!

    Had finally a working Testrun! I grounded my Shield of both Sides! First i did only on the Drive Side. Then, i grounded my Drive Housing -Network Case- (this was the biggest Difference) And i gave my Lighthouses Power of an other Circuit, as my Drives.
    Now, only for Optimisation, i will bring all Cable lenght's to short as possible. Maybe then i'm finally satisfied.
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    Last edited: Feb 15, 2021
  6. Dschadu

    Dschadu Member

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    Ah, I knew something was familiar... Glad I could help you in discord :)
  7. Krzysztof Dej

    Krzysztof Dej Active Member

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    Hi where I should put shield on wires? Between psu and motor controller or between motor controller and motors? If I have 2 wires how to connect shield?
  8. Bastiuscha

    Bastiuscha Active Member Gold Contributor

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    I have my shield between Motor and Controller. And the Shields are grounded this way: (i send the Picture, i get from Dschadu)
    [​IMG]
    My Solution is a bit cheaper. :D But on both Sides!
    I also have a Filter in the Power Line. But we have already discussed that in the Thread. :)
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  9. Dirty

    Dirty Well-Known Member Gold Contributor

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    Glad you got it working! :) I had exactyl the same issues. Took me a while to even figure out it was the EMI.

    First I wrapped all cables in aluminum foil and grounded that. That was an improvement but still frequent gray-outs in VR.

    Then I replaced the cables with shielded cables, and it was pretty good. Ferrite cores on top, just to be sure :)

    Additionally I wanted to add line filters on the mains line, but I looked at the attenuation diagram and the attenuation at 10KHz was basically zero. I needed the 10A versions:
    Attenuation.jpeg

    ...so I opted against them.

    Also, the Reverb G2 is much less susceptible to EMI than the Index's Lighthouses.
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    Last edited: Sep 15, 2021
  10. Dirty

    Dirty Well-Known Member Gold Contributor

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    Oh,... can someone tell me which wire gauge the original cables are?

    I am using a 4x0.75mm² (AWG19) sheilded cable, but it is 8mm in outer diameter. Would a 4x0,5mm² (AWG20) cable suffice?
  11. Viktor

    Viktor New Member

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    I am too experiencing the same Problems with Vive Lighthouse Bluetooth disconnects :(

    The Original Cables are 4 x 0.75 mm2
  12. Bastiuscha

    Bastiuscha Active Member Gold Contributor

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    Did you ground everything like me? Do you use a housing for your servodrives?
  13. Viktor

    Viktor New Member

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    My Motion Simulator:
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    It took some time for me to understand that the vive disconnects are related to the servo drivers and not the vive itself.:think

    Here are the steps I am planning to do:
    1. Replace Cables between motor and and drivers with (shorter!) shielded ones (shield grounded on motor and driver side).
    2. Add a (single?) 230Volt AC Filter before the servo drivers.
    3. Check / enhance all ground connections (star connection).
    4. Install the servo drivers inside a full metal server cabinet (still searching for one with perforated metal door that fits under my chair…(?)
    Anything I have forgotten…?

    I will report my results here.
  14. Bastiuscha

    Bastiuscha Active Member Gold Contributor

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    Sounds really good. Don't forget to ground the metal server cabinet. (that made a big difference to me)
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