584,802 active members*
5,088 visitors online*
Register for free
Login
Results 1 to 7 of 7
  1. #1
    Join Date
    Oct 2019
    Posts
    2

    Limit switch setup, grbl/candle.

    Am installing limit switch's on my generic 3018 CNC and the only programming info I could find
    is a video on youtube which changes $21=, $22= and $23= from a "0 to a "1. Worked great for the
    switches but spindle motor no longer turns on and won't "send" the program to the machine.
    Change back to "0 and all is well. On the same subject, spindle motor must be turned on befor sending the program,
    seems like that should happen automatically. In reverse when program is complete and spindle returns to
    the starting point you must hit "abort" to stop the motor. Any info appreciated.

  2. #2
    Join Date
    Oct 2019
    Posts
    2
    Have tried numerous sites for this info, including the author (denvi/candle) without result. Obviously time to try another grbl controller. Any recommendations?? need a controller that is supported and info available. Thanks.

  3. #3
    Join Date
    May 2004
    Posts
    210

    Re: Limit switch setup, grbl/candle.

    Quote Originally Posted by ca280 View Post
    Have tried numerous sites for this info, including the author (denvi/candle) without result. Obviously time to try another grbl controller. Any recommendations?? need a controller that is supported and info available. Thanks.
    GRBL is the same on every controller which are all basically some form of Arduino. Start here. Personally, I would just get an Uno, a screw shield and use external drivers. Super low cost solution.

    Once you go over the general wiki, check out the limit switch page.

    I don't know which video you watched but based on what you did, I'd stay away from their advice.

  4. #4
    Join Date
    Aug 2009
    Posts
    230

    Re: Limit switch setup, grbl/candle.

    I would suggest considering getting a Arduino Mega instead of the Uno if you have any interest at all in exploring other versions of Grbl; or adding any features to it.

    If you don't want to mess around with that; then an Uno (or Mini or Micro - same chip, different physical form-factor) does represent a simple more-or-less plug & play option.

    The version of Grbl for the ATMega328 (which the Arduino Uno is based on) only has 32K of flash space; and Grbl is currently using up just about all of it. The maintainer of Grbl, for the last update, had to go thru and delete or shorten some text strings just to eek out a few extra bytes to make it fit.

    The ATMega2560, which the Arduino Mega 2560 is based on, has 256K of flash on board, and 8K of RAM (instead of the 2K that's present on the '328). This allows for future expansion or using other people's Grbl versions to do things like 4/5 axis setups, lathe operations (yes, I know what you have is a router, but I'm speaking just in general here), or adding a standalone user-interface using parts that 3D printers use (um... fair disclaimer... that last one is my version... and it's something that I still consider a work-in-progress).

    Also, be aware that the pinouts for the standard Uno version and the Mega version are different; and will thus use different CNC boards.

    The official version for the Mega can be found here: https://github.com/gnea/grbl-Mega/
    An experimental version that has 4/5 axis support: https://github.com/fra589/grbl-Mega-5X
    An experimental version that has lathe support https://github.com/HuubBuis/grbl-L-Mega
    My version that has a user-interface based on 3D printer parts: https://github.com/bdurbrow/grbl-Mega

  5. #5
    Join Date
    Mar 2015
    Posts
    409

    Re: Limit switch setup, grbl/candle.

    By setting $21 to 1, you enabled homing. Depending on (HOMING_INIT_LOCK) compiler options set for your GRBL version, GRBL won't do anything until you have performed a homing cycle.

    Just connect a serial terminal (arduino) to your comport and reset the arduino. The status message will show if the machine is in a alarm state.


    The code in the GRBL config.h file
    // If homing is enabled, homing init lock sets Grbl into an alarm state upon power up. This forces
    // the user to perform the homing cycle (or override the locks) before doing anything else. This is
    // mainly a safety feature to remind the user to home, since position is unknown to Grbl.
    #define HOMING_INIT_LOCK // Comment to disable // Comment to disable

  6. #6
    Join Date
    May 2004
    Posts
    210

    Re: Limit switch setup, grbl/candle.

    It looks like candle has an unlock button which should allow you to get past the initial locked state.

    And, yes, longer term a mega is a better choice but I've run some pretty big G-Code files (60K lines) through GRBL on an Uno with no problems. But for the long term, I hope the gnea guys get to an ARM port soon. (I know there are GRBL ARM forks out there but I want mainstream with active development)

  7. #7
    Join Date
    Aug 2009
    Posts
    230

    Re: Limit switch setup, grbl/candle.

    And, yes, longer term a mega is a better choice but I've run some pretty big G-Code files (60K lines) through GRBL on an Uno with no problems.
    An Uno will run any volume of G-Code you want - it does it a few lines at a time; and the PC sends the next one when the Uno is ready for it. The issue isn't the volume of G-Code; it's adding new G or M codes or other features to Grbl itself.

    Quite frankly, it's remarkable that Grbl can, in fact, do what it can do on a 16Mhz 8-bit processor. There's very little hardware assistance provided for doing the step generation - basically, just some timers that trigger interrupts. All the rest is software - and you get a stable 30Khz step pulse train out of it.

    But for the long term, I hope the gnea guys get to an ARM port soon. (I know there are GRBL ARM forks out there but I want mainstream with active development)
    Yup. In writing my UI support code; I've been rather careful to not modify the main Grbl system much, with the intent to make it reasonably straightforward to integrate it into the official ARM version. I do however, expect to need to do my own PCB with the larger version of the SAMD21 on it; as the official target (the Arduino Zero) just doesn't have enough outputs; and - as of yet - there's no "Arduino Zero Mega".

    P.s. - Gnea is just one guy; Sonny "Chamnit" Jeon... and he's had his life flipped-turned upside down of late. (Hmm... seems like there's a possibility for a TV show there... sitcom, perhaps?)

Posting Permissions

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