Results 1 to 3 of 3

Thread: Limit switch problem?

  1. #1
    Registered
    Join Date
    Apr 2005
    Location
    USA
    Posts
    60
    Downloads
    0
    Uploads
    0

    Limit switch problem?

    Hi,

    I recently got a DoAll mill with an older Centroid M40 3-axis control. When I try to home it, I get a 411 message _axis full power without motion. If I turn off the bottom Z (-) limit switch via the DIP switch, then everything works fine. It will home, run programs and do everything I ask. I ohmed the switch, and it seems to be fine and working. I then checked wiring, and there does not seem to be any shorts or opens. It had the right voltage (+5VDC). If I turn it back on (via the DIP switch), the above mentioned problems come back.

    Any ideas on a fix?

    Thank you,
    Bill Gillen


  2. #2
    Registered
    Join Date
    Feb 2008
    Location
    United States
    Posts
    141
    Downloads
    0
    Uploads
    0
    You probably have a loose connection in the cabinet, either at the PLC or the servo drive. If the switch itself were faulty, you would get false "407 Z- limit (#?) tripped" messages. Since you only get "411 Z axis full power w/o motion", then the switch is remaining closed as far as the PLC can tell, but the servo drive thinks the switch is open.

    Is this a 1993-1994 M40, with the flat 15/15 PLC board, or a 1994-1996 model with the RTK2 PLC unit (stack of three boards)?

    Try cleaning (with contact cleaner) and reseating the 8-pin Waldom plug where the limit switches plug into the servo drive, and, if you have an RTK2, do the same for the 10-pin Waldom plug on top of the RTK2.

    See http://www.cncsnw.com/ServoLogicPM.htm for an illustration of where the limit switches connect from the RTK2 to the servo drive.


  3. #3
    Registered
    Join Date
    Apr 2005
    Location
    USA
    Posts
    60
    Downloads
    0
    Uploads
    0

    Way to go on the info!

    Thank you cncsnw. I really appreciate the help. I followed the instructions on your Centroid DC Servo Drive Preventive Maintenance page, and it works like a charm now. Also, I have experienced the jerky movement twice before (and broke some bits), and was wondering what I did wrong. Now I can see what happened.

    Again, thank you very much for your help.

    Bill Gillen


Similar Threads

  1. Limit Switch Problem
    By tz1238 in forum Machines running Mach Software
    Replies: 4
    Last Post: 02-07-2008, 05:00 PM
  2. Limit switch problem
    By jimini in forum Mach Software (ArtSoft software)
    Replies: 5
    Last Post: 09-17-2007, 09:49 PM
  3. Mach3 limit switch problem on Ref Home
    By originator in forum Mach Software (ArtSoft software)
    Replies: 1
    Last Post: 03-13-2006, 09:02 AM
  4. Problem With IH Limit Switch.
    By Willyb in forum Industrial Hobbies (Support forum)
    Replies: 5
    Last Post: 11-06-2005, 06:17 PM

Posting Permissions



About CNCzone.com

    We are the largest and most active discussion forum from DIY CNC Machines to the Cad/Cam software to run them. The site is 100% free to join and use, so join today!

Follow us on

Facebook Dribbble RSS Feed


Search Engine Friendly URLs by vBSEO ©2011, Crawlability, Inc.