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  1. #1
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    Join Date
    Nov 2022
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    5

    VFD and CNC connundrum

    Hello
    Sorry if this is in an inappropriate place, feel free to move it.
    I am fairly new to CNC and have just bought and assembled a machine from Bulkman3d, it took some time as i have recently had a stroke and have poor memory and a strength\fatigue issue.
    That said, i have been "commissioning" the build and have come across an unusual issue that i would like some advice on. The spindle runs on a VFD, with the system using a xPro V5. I just set up the limits and they are working fine but have noticed that when i start the spindle, the xPro reports that the Z axis has tripped the limit. This is not the case and the two are not physically connected yet either !
    The two are mounted on a board, along with a Power supply ( for xPro) and an E-Stop. They are, i feel, sufficiently distanced to not cause interference between each other and not currently physically connected.
    Anyone any ideas how it is getting tripped please ?

    FYI
    xPro V5 grbl controller with 4 motors and 3 limit switches ( 1 per axis)
    Huanyang VFD 220v connected to 2.2Kw Water cooled spindle

    i can provide more info if required ( if i know it)

    thanks in advance

  2. #2
    Member
    Join Date
    Apr 2004
    Posts
    5579

    Re: VFD and CNC connundrum

    It might be that you haven't sufficiently shielded the wires going to the spindle. These put out powerful RF current that can be picked up by logic-level signal wires with results like you're noticing.
    Andrew Werby
    Website

  3. #3
    Member
    Join Date
    Jan 2005
    Posts
    14722

    Re: VFD and CNC connundrum

    Quote Originally Posted by JonnyDexter View Post
    Hello
    Sorry if this is in an inappropriate place, feel free to move it.
    I am fairly new to CNC and have just bought and assembled a machine from Bulkman3d, it took some time as i have recently had a stroke and have poor memory and a strength\fatigue issue.
    That said, i have been "commissioning" the build and have come across an unusual issue that i would like some advice on. The spindle runs on a VFD, with the system using a xPro V5. I just set up the limits and they are working fine but have noticed that when i start the spindle, the xPro reports that the Z axis has tripped the limit. This is not the case and the two are not physically connected yet either !
    The two are mounted on a board, along with a Power supply ( for xPro) and an E-Stop. They are, i feel, sufficiently distanced to not cause interference between each other and not currently physically connected.
    Anyone any ideas how it is getting tripped please ?

    FYI
    xPro V5 grbl controller with 4 motors and 3 limit switches ( 1 per axis)
    Huanyang VFD 220v connected to 2.2Kw Water cooled spindle

    i can provide more info if required ( if i know it)

    thanks in advance
    Yes, this is very easy to happen, how have you wired the VFD Drive to the spindle and do you have an EMI Power Filter on the input power feed to the Spindle

    Does the 4th pin on the spindle plug have continuity to the spindle body if not the Ground wire inside is not connected, and will have to be corrected.
    Mactec54

  4. #4
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    Jun 2005
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    1568

    Re: VFD and CNC connundrum

    I agree with the other two guys this is an EMI noise issue. Make sure you are using shielded spindle motor cable with copper braid not just foil. Also check the grounds many spindles are missing grounds

  5. #5
    Member
    Join Date
    Nov 2022
    Posts
    5

    Re: VFD and CNC connundrum

    thanks for the feedback. i think i need to remove the Z cable from the cable drag chain and see if the issue rectifies (or moves backward down the gantry to the X). The motor cable has copper foil and a white coloured paper(??) around the cables, so no idea how much shielding they provide but it is the supplied cable. The aviation plug is grounded on Pin 4 (in line with wiring info) and apart from slightly dodgy soldering seem ok, although the limit switch is nowhere near the plug end.
    I will report back my findings in due course.

    thanks

  6. #6
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    Jan 2005
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    14722

    Re: VFD and CNC connundrum

    Quote Originally Posted by JonnyDexter View Post
    thanks for the feedback. i think i need to remove the Z cable from the cable drag chain and see if the issue rectifies (or moves backward down the gantry to the X). The motor cable has copper foil and a white coloured paper(??) around the cables, so no idea how much shielding they provide but it is the supplied cable. The aviation plug is grounded on Pin 4 (in line with wiring info) and apart from slightly dodgy soldering seem ok, although the limit switch is nowhere near the plug end.
    I will report back my findings in due course.

    thanks
    How is your power supplied to your machine do you have just the 240v supply that supplies the whole machine??

    When I said to check the Ground on the 4th pin that is on the Spindle side, not the cable side that you would have terminated, this you need to check to see if it has continuity to the Spindle body, 95% of these spindles do not have the Ground connected and this has to be corrected the snip is what normally has to be done to correct the Ground on the Spindle

    Post some Photos of the wiring, how have you terminated the Shielded cables Shield??
    Mactec54

  7. #7
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    Join Date
    Nov 2022
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    5

    Re: VFD and CNC connundrum

    HI

    The spindle is on the VFD separately, i have connected the 4th pin to ground at the spindle (it came with 4 core cable) with the other end earth in the VFD itself. It has a 'copper paper' type shield so it has not been connected to anything.
    I went through the whole drag chain assembly yesterday so the water pump tubing is taped to the motor cable between the motor and the limits & stepper cabling (these are taped together as well).

    This seems to have cured the issue for now although not ideal. I will try to work with it like this for the moment and look at changing it out later.
    Everything appears to be running as expected but i would like to use the rs484 connection to allow software control of the spindle, but haven't got the correct wiring info as yet.

    If anyone knows which terminals to connect the 2 wires too in the Huanyang, this would be a great help.

  8. #8
    Member
    Join Date
    Jan 2005
    Posts
    14722

    Re: VFD and CNC connundrum

    Quote Originally Posted by JonnyDexter View Post
    HI

    The spindle is on the VFD separately, i have connected the 4th pin to ground at the spindle (it came with 4 core cable) with the other end earth in the VFD itself. It has a 'copper paper' type shield so it has not been connected to anything.
    I went through the whole drag chain assembly yesterday so the water pump tubing is taped to the motor cable between the motor and the limits & stepper cabling (these are taped together as well).

    This seems to have cured the issue for now although not ideal. I will try to work with it like this for the moment and look at changing it out later.
    Everything appears to be running as expected but i would like to use the rs484 connection to allow software control of the spindle, but haven't got the correct wiring info as yet.

    If anyone knows which terminals to connect the 2 wires too in the Huanyang, this would be a great help.
    So, if you are using a separate Power connection to the VFD and another connection to the Drives / Power supplies Etc. then you will have a Ground / Earth loop

    It does not sound like the shielded cable is of the correct type, the Shield won't be doing anything apart from being an antenna, without it being correctly Terminated the Shield need to be clamped at both ends to the Ground Plane
    Mactec54

  9. #9
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    Join Date
    Nov 2022
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    5

    Re: VFD and CNC connundrum

    Sorry for the delay - thanks for the advice. It seems to run ok now, although having to manually switch it separately is not ideal but will have to do until i find the solution. I will upgrade the cabling for the spindle to fully shielded if i find i get any issues but, for the moment it will do as i am a light user.

    thanks to all who lent a hand and advice.

  10. #10
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    Join Date
    Jul 2018
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    4471

    Re: VFD and CNC connundrum

    Hi - In Home built CNC machines page they suggest you use a a "good earth" see attached... Peter

  11. #11
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    Join Date
    Nov 2022
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    5

    Re: VFD and CNC connundrum

    Hi - not a home built unit - its a "Ultimate Bee" from bulkman3d. Just finding a few issues with the information they supply- or not as the case may be. And the little aches and pains that does not help their cause!
    thanks

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