Need Help! VF3 Run Away X Axis


Results 1 to 14 of 14

Thread: VF3 Run Away X Axis

  1. #1
    Member
    Join Date
    Mar 2003
    Location
    United States
    Posts
    63
    Downloads
    0
    Uploads
    0

    Default VF3 Run Away X Axis

    I have a 1995 VF3
    In the middle of drilling a hole pattern I heard what sounded like a bit snapping and sure enough the drill bit had snapped. It looks when drilling it started to wander a little to the +X direction while pecking (picture enclosed). It then started to 100% rapid move in +X direction. I tried to stop it by pressing "Reset" but it kept going and only stopped because it ran to the X limit.

    The resulting Errors were...
    108 X Servo Overload
    103 X Following Error Too Large
    but I think these only resulted because it went to the X limit and are not the root of the problem of running away in X direction.

    The following I've done to try and Trouble shoot...
    1) Re-Home everything. The Z axis will home but X axis does the 100% Rapid run away in -X direction till it goes to the limit and the 103 X Following error comes up. I can home Z and Y when using "ZERO SINGL AXIS"
    2) I Swapped the X and Y motor cards but exact same problem, when homing X it runs away but Y is fine so I'm assuming the Motor Boards are not the problem.
    3) When homing the X alone it does the 100% Rapid runaway and the only way to stop it is using E-Stop. The 108 and 103 Alarms do NOT result.
    4) I replaced the X cable a few years ago but I can't visually see any problems with it.

    I have another issue that I'm not sure is related or not...
    When drilling a hole pattern with something like
    G0 G90 G54 X0.0 Y0.0;
    G99 G81 Z-1.0 R0.1 F5.0;
    X1.0Y1.0;
    ... my mill used to drill the 1st hole at X0.0 Y0.0 but now although it goes to X0.0 Y0.0 it doesn't drill there but skipps it and goes to X1.0 Y1.0 and starts drilling there.
    My work around is to make sure the initial G81 line has the X and Y positions and using
    G99 G81 X0.0 Y0.0 Z-1.0 R0.1 F5.0;
    I thought maybe there was a setting I accidentally switched but I couldn't find it.

    I'm guessing it's the X encoder or X cable...
    Any other ideas would be appreciated

    Similar Threads:
    Attached Thumbnails Attached Thumbnails VF3 Run Away X Axis-runawayx-jpg  
    xeno@xenomechanics.com
    http://www.xenomechanics.com


  2. #2
    Registered
    Join Date
    Mar 2014
    Location
    United States
    Posts
    133
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    could be these following issues, motor,processor board,mocon board, motor cable,software.



  3. #3
    Member dertsap's Avatar
    Join Date
    Oct 2005
    Location
    canada
    Posts
    4230
    Downloads
    1
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    have you verified that there is no crud on the x home switch .

    A poet knows no boundary yet he is bound to the boundaries of ones own mind !! ........


  4. #4
    Member
    Join Date
    Mar 2003
    Location
    United States
    Posts
    63
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Looking at the X home switch everything looks fine. Attached is a pictureVF3 Run Away X Axis-xhomeswitch-jpg
    I'm glad it was suggested as you can see the switch rolled half way up the ramp. I can still turn the X axis screw so the bed would keep going in the -X direction, which is the direction it homes which indicates the limit switch had something to do with stopping the X runaway, meaning that there wasn't a hard physical stop, but a software/hardware stop.

    So although I confirmed my Motor Servo Board is probably ok (switching X and Y servo boards problem stayed with X). I'm not sure what the processor Board and mocon board would be. My Manual has a "Motor Interface PCB" and "Servo Distrubution Card".
    Any ideas how to trouble shoot from here?

    xeno@xenomechanics.com
    http://www.xenomechanics.com


  5. #5
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5717
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    The Following Error should have shut the servos down. That error normally means that the position error (Commanded Position vs. Actual Position) has exceeded the set value. This is normally caused by an encoder feedback failure. Could be encoder (or resolver, if equipped), cable, board, or the servo drive depending on how things are wired up.



  6. #6
    Registered
    Join Date
    Mar 2014
    Location
    United States
    Posts
    133
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Xeno, the processor board takes the information given from the motor interface board/Mocon board is just a newer revised board for brushless machines. Technically the servos should have shut off, but unfortunately I'm seen some rare occasions that it doesn't until it feeds the axis into a hard stop.That would be due to one of those boards, processor/motor interface board. The power distribution board supplies the axis amp boards with their power. Although if you switched the axis amp boards and the problem still stayed with x it could be motor,motor cable,motor interface board,processor ( the only reason why I'm suggesting that is due to the fact the board is not commanding the servos to shut off if it has a problem. If your roller switch was bad the x axis should typically start homing out in the opposite direction of its typical home position. Also one last thing Haas has never built motors with resolvers. If it is possible feedback it with be the encoder on your motor.



  7. #7
    Member
    Join Date
    Mar 2003
    Location
    United States
    Posts
    63
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    I'd like to try and test/see the output of the encoder as I have access to o-scopes etc.

    I assume the X roller switch is what I called the X home/Limit switch which I have a picture of above. With Diagnostics on the monitor, I can see the "X HOME" toggle from 0 to 1 every time I manually push the limit switch down so it's probably functioning correctly.

    When I power up the VF3, on the Diagnostic screen I have...
    0 X-Axis Z Channel
    1 Y-Axis Z Channel
    1 Z-Axis Z Channel
    1 A -Axis Z Channel
    These values don't change even when I Single Home the Y and Z

    I"m thinking about swapping the X and Z motors as I'm pretty sure they are the same. The Y motor is pain to get off and even worse to put back in.

    As usual I appreciate everyone's input...
    Tony

    xeno@xenomechanics.com
    http://www.xenomechanics.com


  8. #8
    Member
    Join Date
    Mar 2003
    Location
    United States
    Posts
    63
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Update...
    I was able to switch the X and Z motors.
    The Z axis now runs away (Rapid move upward) when It's being homed. I stopped it with the E-Stop as I didn't think it was worth taking the chance of damaging anything.
    The X and Y axes I am able to home.

    I think this isolates it to the Encoder. I don't think the Motor it self would be the problem?

    xeno@xenomechanics.com
    http://www.xenomechanics.com


  9. #9
    Member
    Join Date
    Mar 2003
    Location
    United States
    Posts
    63
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Replaced the Encoder and now it works.

    I can't see any obvious damage to the one that was replaced. Some of the dust from the brushes (Graphite?) could of gotten into it but it's probably unlikely that caused the problem....

    xeno@xenomechanics.com
    http://www.xenomechanics.com


  10. #10
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5717
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Happy to hear you got it running again.



  11. #11
    Member
    Join Date
    Mar 2003
    Location
    United States
    Posts
    63
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Thanks JIm!

    One thing that I didn't expect....
    I checked the G54 and G55 locations and the X seemed to of shifted +.070
    I did replace the encoder but I thought it had amnesia when it's powered down, and it picks up the X home postion from the x Limit switch and trip neither of which I moved.

    xeno@xenomechanics.com
    http://www.xenomechanics.com


  12. #12
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5717
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Maybe an absolute encoder? If that's the case, you may have to ''clock'' the encoder on the shaft. Or maybe there is a parameter you can set. If it is an incremental encoder, you may still have to clock it to get the index pulse in the right place. Many machines use the index pulse for the final homing move.



  13. #13
    Registered
    Join Date
    Feb 2010
    Location
    USA
    Posts
    1184
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    Quote Originally Posted by Xeno View Post
    Thanks JIm!

    One thing that I didn't expect....
    I checked the G54 and G55 locations and the X seemed to of shifted +.070
    I did replace the encoder but I thought it had amnesia when it's powered down, and it picks up the X home postion from the x Limit switch and trip neither of which I moved.
    Once the limit switch is triggered, the motor backs off the switch an amount set in parameters. Depending on where the encoder shaft was positioned in relation to the pulse mark when you reconnected it to the motor will determine it's final position, so it's not a surprise that you see a small change in location.



  14. #14
    Registered
    Join Date
    Mar 2014
    Location
    United States
    Posts
    133
    Downloads
    0
    Uploads
    0

    Default Re: VF3 Run Away X Axis

    The parameter is called your x-axis grid offset. Once it triggers the home switch the value that is under your x-axis grid offset will adjust your amount it shifts off your home switch. Each axis has it own grid offset.



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

VF3 Run Away X Axis

VF3 Run Away X Axis