intermittently stepping the wrong direction in z


Results 1 to 8 of 8

Thread: intermittently stepping the wrong direction in z

  1. #1
    Registered
    Join Date
    Jan 2008
    Location
    united state
    Posts
    16
    Downloads
    0
    Uploads
    0

    Default intermittently stepping the wrong direction in z

    Guys,

    Having a strange issues that started last night.

    I have isolated it down to the z intermittently step up when it was commanded to step down; only while the spindle is running.

    So my cuts keep getting shallower as the code runs on. If it disable the spindle, and check my zero after running a program; its spot on. if i let the spindle run, i can be as much a .500 above the orgin point!

    4X4 pro with linear bearings
    chinese spindle
    mx4660
    leadshine NEMA 34 stepper.
    been setup and running for 2 plus years

    The only thing that has recently changed is setting the dust collection up so mach can turn it on and off, but that was 1 weeks ago.
    Have been running the machine pretty constant for the last 6 weeks. That is probably the biggest change..

    thanks for any sugjestions.

    landy

    Similar Threads:


  2. #2
    Registered
    Join Date
    Sep 2005
    Location
    USA
    Posts
    888
    Downloads
    0
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    My best guess is RF or Electrical noise from the VFD getting into your Z controller. Strange it should start just now. Check all your grounds and grounding, and loose connections in the VFD box and controller enclosure. You might have moved or rerouted some wires around and that made it happen. I am thinking your running Mach3?

    Retired Master Electrician, HVAC/R Commercial union shop and Lots of hobbies. FLA Saturn 2 4x4 CNC Router


  3. #3
    Registered
    Join Date
    Jan 2008
    Location
    united state
    Posts
    16
    Downloads
    0
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    Quote Originally Posted by wmgeorge View Post
    My best guess is RF or Electrical noise from the VFD getting into your Z controller. Strange it should start just now. Check all your grounds and grounding, and loose connections in the VFD box and controller enclosure. You might have moved or rerouted some wires around and that made it happen. I am thinking your running Mach3?
    Thanks for the response George.
    Yes, running mach 3.

    I adjusted the Max Step frequency in the ESS control panel in mach 3. It was set @ 256, took it down to 128 and ran the program with the spindle. After check the zero, I had lost .013 on the z. so this is a large improvement, but not acceptable.
    just dropped it down the 64Khz and see what it does.

    Did this because after re-reading the MX4660 manual, it appears the max step frequency is 250? not sure how it worked for years @ 256.

    anyways, hopefully @ 64Khz I wont lose any z...



    landy



  4. #4
    Registered
    Join Date
    Sep 2005
    Location
    USA
    Posts
    888
    Downloads
    0
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    Quote Originally Posted by landy View Post
    Thanks for the response George.
    Yes, running mach 3.

    I adjusted the Max Step frequency in the ESS control panel in mach 3. It was set @ 256, took it down to 128 and ran the program with the spindle. After check the zero, I had lost .013 on the z. so this is a large improvement, but not acceptable.
    just dropped it down the 64Khz and see what it does.

    Did this because after re-reading the MX4660 manual, it appears the max step frequency is 250? not sure how it worked for years @ 256.

    anyways, hopefully @ 64Khz I wont lose any z...



    landy
    Your real problem is either a ground or shielded cable ground. Those connections can go bad, loose or corroded connection.

    Retired Master Electrician, HVAC/R Commercial union shop and Lots of hobbies. FLA Saturn 2 4x4 CNC Router


  5. #5
    Registered
    Join Date
    Apr 2010
    Location
    Canada
    Posts
    70
    Downloads
    0
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    The ESS has a setting to debounce signals - When I first set up my 2.2KW spindle/VFD, I had to make an adjustment in that setting due to noise from the VFD. In your case, I have no idea why it should start now, but that's the setting I would tweak. https://warp9td.com/index.php/faq/faq-mach3#Debounce



  6. #6
    Registered
    Join Date
    Nov 2015
    Posts
    15
    Downloads
    0
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    Landy, I had an issue where static would build up in the wire on my flexible dust collection hose and arc to the spindle. a simple grounding of the spiral wire eliminated this from happening anymore. I don’t know if it applies to you, but worth mentioning
    Cheers
    Sean



  7. #7
    Registered
    Join Date
    Apr 2004
    Location
    Oakland CA USA
    Posts
    4657
    Downloads
    0
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    The other thing I'd check would be the braided wire shield that should be covering your spindle leads, that's supposed to be grounded on one end only (usually the VFD end). If your machine only malfunctions when the spindle's turned on, that's usually the problem - those wires transmit a lot of RF interference, which are captured by the braided shield acting as a Faraday cage.

    As Smeltvedt points out, the dust collector can also produce static electricity that can interfere with signals. Any non-conductive tubing must have an uninsulated multistrand wire running up the inside that's grounded to collect that static charge.- skipping that step can lead to explosions and fires in the dust collection system.

    [FONT=Verdana]Andrew Werby[/FONT]
    [URL="http://www.computersculpture.com/"]Website[/URL]


  8. #8
    Registered
    Join Date
    Jan 2005
    Location
    USA
    Posts
    1760
    Downloads
    2
    Uploads
    0

    Default Re: intermittently stepping the wrong direction in z

    Another thing that you can check is there should be a setting for how long the program has to wait after a direction change before it sends a step pulse. For example, the drives in one machine of mine requires 5uS after a direction change before sending a step pulse, otherwise it could go the wrong way.



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

intermittently stepping the wrong direction in z

intermittently stepping the wrong direction in z