Welcome to Our Community

Some features disabled for guests. Register Today.

Ask Grbl CNC questions here.

Discussion in 'Control Software' started by Sonny Jeon, Aug 12, 2015.

  1. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    and then 'do the math' (-:
    HOWTO Calibrate your CNC Machine for MACH3 or GRBL
     
  2. Saint Billy

    Saint Billy Journeyman
    Builder

    Joined:
    Dec 1, 2016
    Messages:
    67
    Likes Received:
    7
    All sorted, cutting to correct depth now, onwards and upwards. Leadscrew steps were wrong.

    Thanks guys
     
    David the swarfer likes this.
  3. DaveH24

    DaveH24 Well-Known
    Builder

    Joined:
    Feb 19, 2017
    Messages:
    17
    Likes Received:
    1
    Hi

    I'm using grbl-Mega to control a home-brew cnc lighweight router currently with a 400w dc motor .
    I've just ordered a 800w VFD to upgrade it.

    Has anyone tried to control one of these over the RS485 port from a Mega ?
    The Mega has extra TTL level serial ports which could easily be connected , and accessed using Serial1.begin ......

    I've looked at the spindle speed code and it looks like an easy job to insert the relevant code in there.

    What is the enormous pitfall that I'm missing ? :)

    Regards

    Dave
     
  4. Sonny Jeon

    Sonny Jeon Veteran
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2015
    Messages:
    147
    Likes Received:
    47
    Grbl doesn't use any Arduino code and will break if you try to.
     
  5. DaveH24

    DaveH24 Well-Known
    Builder

    Joined:
    Feb 19, 2017
    Messages:
    17
    Likes Received:
    1
    Well I guess that is a fairly major pitfall, any pointers as to how I could go about this ?

    Regards

    Dave
     
  6. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Hey Sonny (or anyone)

    I recently acquired a Laser setup for my machine. Can't figure out how to get it going. I have V1.1F. Laser mode is enabled. Min speed = 0, max speed =255.
    The laser works when I connect the enable line to +5v. I cannot get any voltage on the PWM output D11. I have put in |M3 with S=varying values, but the laser does not come on. Help?
     
  7. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Is perhaps the D11 output open drain? Do I need to connect the laser enable (+) to 5v and (-) to D11? Or (+) to d11 and (-) to ground?
     
  8. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    An update, I got it to work if I turned laser mode off ($32=0). M3 and M5 turn the laser on and off in this mode. It does not output PWM if $32=1.
    Is this a bug?

    MG
     
    #458 Metalguru, Feb 21, 2017
    Last edited: Feb 21, 2017
  9. Ferreri

    Ferreri Well-Known
    Builder

    Joined:
    Feb 1, 2017
    Messages:
    18
    Likes Received:
    4
    Are you trying to cut/engrave something or just turning the laser on and off?
    The laser should only be activated on a speed controlled move. That is not a bug... I'd imagine it's to help people from burning down their house.
    Grbl v1.1 Laser Mode · gnea/grbl Wiki · GitHub
     
  10. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Yeah, but apparently if you use M3 instead of M4, the laser should turn on regardless. Only if you use M4 should it be movement dependent.

    And yes, I read the Wiki.

    MG
     
  11. Ferreri

    Ferreri Well-Known
    Builder

    Joined:
    Feb 1, 2017
    Messages:
    18
    Likes Received:
    4
    I'm sorry, I wasn't trying to imply that you didn't read the wiki... Just trying to help.
    Did you just try "G1 M3 S255"? Did you get an OK response?
     
  12. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    No, I didn't put them all on the same line. Nor did I use a G1. These steps should not be necessary if you have laser mode off, I didn't think it would be required if you have laser mode on, either. I'll play with it more tomorrow. I was able to get it to work OK with laser mode off and a simple g-code engraving file just by search and replacing all the "move Z up" commands with M5 and all the "move Z down" commands by M3, and setting S255 at the beginning of the file.

    MG
     
  13. Ferreri

    Ferreri Well-Known
    Builder

    Joined:
    Feb 1, 2017
    Messages:
    18
    Likes Received:
    4
    Same line shouldn't matter... It's the G1 that matters. The laser will only turn on when Grbl is in a G1, G2, or G3 motion mode.
     
  14. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    you need to read the manual! -> Grbl v1.1 Laser Mode · gnea/grbl Wiki · GitHub
    summary:
    with $32=1 the PWM output only comes on when there is MOTION
    M3 will cause the laser to come on instantly to the S value when G1/G2/G3 is issued
    M4 will cause the laser to come on in proportion to the acceleration when G1/G2/G3 is issued. this prevents burning 'extra' in corners.

    (edit)
    I have just been fiddling with this mode. To turn the laser on and off there has to be actual motion.
    in other words, the commands
    Code:
    G21 M3 S1000 F100
    G0 X10
    G1 X10
    
    will NOT turn the laser on because there is no motion in X
    Code:
    G21 M3 S1000 F100
    G0 X10
    G1 X10.1
    
    WILL turn the laser on, because X moves 0.1mm

    I don't think the Wiki is completely clear about this.
     
    #464 David the swarfer, Feb 22, 2017
    Last edited: Feb 22, 2017
  15. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    from the wiki...
    • The laser will only turn on when Grbl is in a G1, G2, or G3 motion mode.
      • In other words, a G0 rapid motion mode or G38.x probe cycle will never turn on and always disable the laser, but will still update the running modal state. When changed to a G1 G2 G3 modal state, Grbl will immediately enable the laser based on the current running state.

      • Please remember that G0 is the default motion mode upon power up and reset. You will need to alter it to G1, G2, or G3 if you want to manually turn on your laser. This is strictly a safety measure.

      • Example: G0 M3 S1000 will not turn on the laser, but will set the laser modal state to M3 enabled and power of S1000. A following G1 command will then immediately be set to M3 and S1000.

      • To have the laser powered during a jog motion, first enable a valid motion mode and spindle state. The following jog motions will inherit and maintain the previous laser state. Please use with caution though. This ability is primarily to allow turning on the laser on a very low power to use the laser dot to jog and visibly locate the start position of a job.
    (edit): PS: I have edited the Wiki to say that actual motion is required for the laser to turn on.
    more PS: turns out I see this behavior in the ArduinoIDE serial console and in GRBL-Panel, but NOT in UGS. @Sonny Jeon
     
    #465 David the swarfer, Feb 22, 2017
    Last edited: Feb 22, 2017
  16. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    SketchUcam can generate this code with one extra mouse click (-:
    'Laser mode' checkbox on the parameters dialog. The $32 mode does not actually matter (-:
    and if you want to use M4 mode with $32=1 then you can, read the help for laser mode.
     
  17. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    The Wiki also says:

    "NOTE: M3 can be used to keep the laser on for focusing."

    This would imply that motion is not required for this mode.

    MG
     
  18. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Unfortunately, SketchUCam, or more precisely SketchUp, cannot import JPEG or BMP files to convert to laser images. Not a limitation of SketchUCam, but of Sketchup. It is their choice to leave the free version brain dead with regards to import/export of graphics formats. So, if I want to laser a tribal tattoo on my arm, SketchUCam is not an option.;)

    MG
     
    David the swarfer likes this.
  19. Ferreri

    Ferreri Well-Known
    Builder

    Joined:
    Feb 1, 2017
    Messages:
    18
    Likes Received:
    4
    "The laser will only turn on when Grbl is in a G1, G2, or G3 motion mode."
     
  20. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Yes, when using M4 only. What I get from the Wiki is that using M3 does not require movement to turn the laser on. I have verified this with my laser setup here, but not in laser mode.

    MG
     
  21. Ferreri

    Ferreri Well-Known
    Builder

    Joined:
    Feb 1, 2017
    Messages:
    18
    Likes Received:
    4
    I think we're interpreting things differently:
    Example: G0 M3 S1000 will not turn on the laser, but will set the laser modal state to M3enabled and power of S1000. A following G1 command will then immediately be set to M3 and S1000. Note that from some GUI's (like the Arduino serial console) there must be ACTUAL MOTION in the G1 command, G0 X10 followed by G1 X10 will NOT turn the laser on (but in UGS it WILL turn on).

    This is all with Laser Mode enabled.
     
  22. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    I am using GRBL Panel. Perhaps this is the issue. In this case, how in the Sam Hill do you focus the laser?

    MG
     
    David the swarfer likes this.
  23. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    you make it MOVE (pretty sure I did point this out?)
    issue the manual commands:
    M3 S1 F10 ; set parameters
    G0 X10 ; go somewhere, can be where you are now
    G1 X10.1 ; move just a little bit, laser will turn on
    after focusing, then
    G0 X10 ; turn it off
    OR
    M5 ; turn it off

    BE CAREFUL with LASERS
    I noticed that in UGS using the Y+ Y- etc buttons will turn the laser ON if M# or M$ is active and S > 0, even though what you think you are doing is 'jogging'.
    issue a M5 before jogging! just tested GRBLPAnel 1.0.9.13 and it does the same, if an M3 or M4 has been issued, jogging will turn the laser on.
     
  24. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    no, in both M3 and M4 it will only turn on when there is motion, when $32=1
    this is the whole point of the laser mode in that the laser is only on when there is cutting motion and automatically off when there is non-cutting (G0) motion. This is safer, and saves a lot of Gcode being sent, which results in faster raster image processing.
     
  25. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Ok. I think I've got it now. Unfortunately, my laser machine just shipped out the door. I will relay this info to the client.

    Seems the Wiki is more than a bit ambiguous. I read it at least 5 times and still didn't get this. It does say "Constant laser power mode (M3) simply keeps the laser power as programmed, regardless if the machine is moving, accelerating, or stopped." This pretty much tells me that if you send an M3, the laser is on.

    I agree that the laser should not be turned on when jogging. This could easily ruin a work piece, not to mention your eyeballs. Seems though that up to now, the jog controls (in GRBL Panel, at least) just work by sending g-codes to GRBL. I think I read somewhere that the latest version does jogging differently.

    MG
     
    #475 Metalguru, Feb 23, 2017
    Last edited: Feb 23, 2017
  26. Metalguru

    Metalguru Master
    Builder

    Joined:
    Dec 29, 2015
    Messages:
    423
    Likes Received:
    250
    Update:

    Apparently the laser on during Jog mode was a request from users. From the Wiki:

    "To have the laser powered during a jog motion, first enable a valid motion mode and spindle state. The following jog motions will inherit and maintain the previous laser state. Please use with caution though. This ability is primarily to allow turning on the laser on a very low power to use the laser dot to jog and visibly locate the start position of a job."

    MG
     
  27. Richard Watson

    Richard Watson Well-Known
    Builder

    Joined:
    Dec 28, 2016
    Messages:
    13
    Likes Received:
    2
     
  28. Richard Watson

    Richard Watson Well-Known
    Builder

    Joined:
    Dec 28, 2016
    Messages:
    13
    Likes Received:
    2
    Hi I am newbie
    I have constructed a c-beam router, managed to test ok But on my first protect, I cannot get the cutter to reach the work piece ,I have watched the video on sketchup but nothing works, so I have tried a simple circle to eliminate problems with my design .it starts to cut the circle then stops with an error (open door) if I cancel the error it carries on back to the same place then the (open door ) code
    thank you
    Richard
     
  29. David the swarfer

    David the swarfer OpenBuilds Team
    Staff Member Moderator Builder

    Joined:
    Aug 6, 2013
    Messages:
    775
    Likes Received:
    357
    Do you have a safety door switch connected to the 'feed hold' pin?
    If you do then that wiring needs to be shielded or otherwise guarded against electrical interference.

    If you do not have anything connected then interference is getting into pin A1 somehow. Can you connect a 2k resistor between that pin and the 5v pin? This will help it resist interference.

    But also, why is the door feature turned on if you do not have a door switch?

    As for not reaching the workpiece.... what GUI are you using?
    Also, are you using the workpiece top as z-zero, or table top as z-zero? (That is a setting in SketchUcam)
     
  30. Richard Watson

    Richard Watson Well-Known
    Builder

    Joined:
    Dec 28, 2016
    Messages:
    13
    Likes Received:
    2
    Hi David
    Thank you for your prompt reply.
    As I stated I am very new to cnc ,
    I am not sure what GUI is sorry. I have built a basic C beam machine with
    CNC xPRO V3 Controller Stepper Driver,
    with the Grbl panel,I set the workpiece top as zero in SketchUcam.
    I do not have a door switch or even a door as yet,
    I created a simple design of a square and a circle inside ,applied the outer cut to the square and the inner cut to the circle, it cut the circle ok in small layer steps but each time at the same place it would stop and display open door I would click reset an it would jump approximately a quarter inch this would continue until the circle was cut,it then moved to cut the square but just traced the pattern without dropping on to the work piece ,it would also stop at the same place and error code open door.
    thanks
    Richard
     

Share This Page