585,585 active members*
3,912 visitors online*
Register for free
Login
Results 1 to 6 of 6
  1. #1
    Join Date
    May 2015
    Posts
    23

    Closed loop control in PlanetCNC

    Is it possible to have position read from scales or encoder vs counting steps?

    Sent from my LG-D722 using Tapatalk

  2. #2
    Join Date
    Mar 2017
    Posts
    1304

    Re: Closed loop control in PlanetCNC

    PlanetCNC controller will not read position from scales or encoder. Most modern servo drivers and some stepper drivers will do this. After all, it is drivers "job" to position motors where it was instructed to.

  3. #3
    Join Date
    May 2015
    Posts
    23

    Re: Closed loop control in PlanetCNC

    Quote Originally Posted by PlanetCNC View Post
    PlanetCNC controller will not read position from scales or encoder. Most modern servo drivers and some stepper drivers will do this. After all, it is drivers "job" to position motors where it was instructed to.
    Thank you for the reply. If I use a servo drive, will it read the absolute position value from the PC in some way or does it also count the step&direction pulses and continuously calculate the required steps? Eg the x axis must move from 0 to 10 mm- the control outputs 100 steps- the servo drive counts 100 step pulses and moves the motor 100 "steps" or more until it reads the required position. Some error could creep in due to rounding.

    Sent from my LG-D722 using Tapatalk

  4. #4
    Join Date
    Mar 2003
    Posts
    35538

    Re: Closed loop control in PlanetCNC

    A servo drive will move the number of steps it receives, and use the encoder's to make sure it moves to that position.
    Whether you send it 100 steps or 10,000 steps, it moves the motor that amount, and uses the encoder to verify that it's at that position. There are no rounding errors.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  5. #5
    Join Date
    May 2015
    Posts
    23

    Re: Closed loop control in PlanetCNC

    Ok, thank you Ger I am eager to add encoders to my existing CNC. Will have to add some circuitry to interface with my encoders and do the positioning.

    Sent from my LG-D722 using Tapatalk

  6. #6
    Join Date
    Mar 2003
    Posts
    35538

    Re: Closed loop control in PlanetCNC

    If your existing machine has steppers, adding encoders is very different from a servo drive, which is what I was talking about. I've never used Planet CNC, but I wouldn't expect it to even support adding encoders to steppers?
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

Similar Threads

  1. Replies: 0
    Last Post: 03-13-2012, 11:15 PM
  2. Replies: 0
    Last Post: 02-10-2011, 03:05 PM
  3. Closed loop control with linear encoders
    By Xerxes in forum LinuxCNC (formerly EMC2)
    Replies: 15
    Last Post: 10-14-2007, 08:04 PM
  4. Closed-Loop stepper control
    By mmjpotter in forum Stepper Motors / Drives
    Replies: 2
    Last Post: 10-09-2006, 09:16 PM
  5. Closed loop PC based control
    By Al_The_Man in forum CNC (Mill / Lathe) Control Software (NC)
    Replies: 2
    Last Post: 09-19-2005, 03:29 AM

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
  •