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Thread: Issue with shielded wires on DIY machine

  1. #21
    Member mactec54's Avatar
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    Default Re: Issue with shielded wires on DIY machine

    Quote Originally Posted by Xenofon9 View Post
    Understood!
    Any tips for improvement with the current set-up? I am in no position to restart the wiring as we stand with the proper ground plane and clamp. In particular how can you do a panel mount connector with this method though ?
    There are many options here are some you can even make your own clamps from 1.5mm aluminum 12mm wide, they must clamp tight around the shield and the Drain wire just wrap that around the shield if you have a drain wire

    Attached Thumbnails Attached Thumbnails Issue with shielded wires on DIY machine-shield-clamp-6-png   Issue with shielded wires on DIY machine-shield-clamp-9-png   Issue with shielded wires on DIY machine-shield-clamp-11-png   Issue with shielded wires on DIY machine-shield-clamp-12-png  

    Issue with shielded wires on DIY machine-shield-grounding-clamps-png   Issue with shielded wires on DIY machine-shield-gland-cable-restraint-png   Issue with shielded wires on DIY machine-shield-clamp-png   Issue with shielded wires on DIY machine-shield-grounding-1-png  

    Mactec54


  2. #22
    Member MML102783's Avatar
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    Quote Originally Posted by Xenofon9 View Post
    Understood!
    Any tips for improvement with the current set-up? I am in no position to restart the wiring as we stand with the proper ground plane and clamp. In particular how can you do a panel mount connector with this method though ?
    You can make I happen . You don’t HAVE TO HAVE every cable 360 degree shield grounded. It is best practice but.... the motor with the issue... is it the VFD motor or one of those 48v drives? Have you measured the resistance of your Field Ground? You can make this work.



  3. #23
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    Quote Originally Posted by Xenofon9 View Post
    Hello,

    I recently finished building my controller for a DIY router machine (image attached).

    I am using 3x these closed loop steppers: https://www.omc-stepperonline.com/cl...5Bnema%2024%5D
    When they arrived I noticed that the motor cable was not shielded.
    I made my own shielded cable assembly for one of the motors, but I am getting some very strange behavior with this (strange for me at least...)

    When I connect the drain wire from that cable to my ground terminal (controller side) and power-on the system the stepper makes a loud whiny noise and nothing really works.
    Any ideas what might be happening ?

    Thanks in advance!!
    You have a poor ground on the signal side of the driver. Shielding the power side is not necessary, just don't run signal cables beside power (or motor) cables. Ground all signal cable shields from one end only, never both ends. Use a totally separate signal ground. Do not tie it to motor shield or earth grounds - doing so will cause a ground loop. Use a star configuration for signal grounds (returns). Earth ground is fine for cabinets and motor shields, not for signals. That is run as an earth bond to major mechanical structures but not signals. The purpose of the shields is to eliminate induced EMI not to provide grounds. A ground block is fine for signal grounds and returns. Grounding everything together is very bad practice. The reason you are having problems is that the ground threshold at your amplifier is bouncing causing false triggering of your inputs. If you have a scope you can check it out. If not try adding a ground from your power supply negative directly to the signal ground on your driver module. Cut the shield loose on one end of every cable. I worked as an EMC/EMI engineer for 30 years. I could care less what some stupid paper says (might be misinterpreted anyway). Also did TEMPEST testing and hardening. Bet you didn't know we could read what you were printing from 200 feet away without shielding to TEMPEST specifications back then (that's EMI).



  4. #24
    Community Moderator Al_The_Man's Avatar
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    Default Re: Issue with shielded wires on DIY machine

    Quote Originally Posted by bainbob View Post
    I could care less what some stupid paper says (might be misinterpreted anyway). .
    That;s funny! , Siemens, a major highly regarded company that has been involved in Industrial electronics since 1847 are 'Stupid"
    I know who I would take advice from first!

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  5. #25
    Member mactec54's Avatar
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    Default Re: Issue with shielded wires on DIY machine

    Quote Originally Posted by bainbob View Post
    I worked as an EMC/EMI engineer for 30 years.
    Wow and still can't get it right

    Quote Originally Posted by bainbob View Post
    I could care less what some stupid paper says,
    Yes we know where you are coming from posting miss information unrelated, to CNC Machine Controls is no help to anyone

    Mactec54


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Issue with shielded wires on DIY machine

Issue with shielded wires on DIY machine