How Do I Setup my Z Probe?

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This topic contains 9 replies, has 4 voices, and was last updated by Profile photo of William William 1 month, 3 weeks ago.

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  • #26415
    Profile photo of P3DCNC
    P3DCNC
    Participant

    Hey gang, I’m trying to find the info on how to setup the Z probe.

    My plan is to use the G38 codes. I’d like to have it touch the plate for Z, then look for both edges. But I’m using Fusion 360 and Repetier, so not ESTLCAM.

    Can I use Repetier and the G38 commands to set the origin of the stock I want to cut?
    Does that work with the Vicious1 RAMPS?
    Do I use the Z min end stop?
    Do I use one of the Aux or Probe pins?
    What do I need to do in the Configuration.h file?

    Anything else?

    #26420
    Profile photo of vicious1
    vicious1
    Keymaster

    I don’t know if it is built into fusion, But I am pretty sure you can just write a little script to do it for you. All it does is move negative, down, slowly positive until it touches and sets that axis to zero, minus the touch plate offset. Repeat that three times and done.

    I have never needed this, all my jobs I make so the starting point is pretty loose. Meaning I make sure all sides and top get surface, effectively making my own zero perfectly.

    #26426
    Profile photo of P3DCNC
    P3DCNC
    Participant

    I tried just running the G38.2 codes and nothing happens. For example G38.2 Z-10 to move 10mm down. Same on X and Y. What gives?

    #26427
    Profile photo of William
    William
    Participant

    Z is pretty straight forward like Ryan says, but if you want to do X and Y it’s a little more involved as you need to take the touch plate offset as well as 1/2 the bit diameter. So try not to find X and Y with a v bit…

    Also remember if you’re using 38.2 that you must be within the distance specified by the command or you will get an error.
    Example: G38.2 Z-10 – you must be within 10 units of the surface.

    You want to set your probe feed rate as well. You do NOT want to try a zero at rapid feed rates!

    I normally will rapid to within 1mm of the probe location, set probe feed rate, then issue the G38.2. Saves a HUGE amount of time.
    And then reset the feed rate or you may die of old age watching the spindle creep slowly across the workpiece…

    #26429
    Profile photo of P3DCNC
    P3DCNC
    Participant

    Sure, but nothing happens when I send the commands. Tried G38.2 -Z10 F1. Should it not be moving? Do I have to set something in the firmware ?

    #26433
    Profile photo of Martin DB
    Martin DB
    Participant

    You need Marlin RC8 or higher. Check carefully the “Z Probe Options” section in Configuration.h file (you can use the same pin for z min home or another one).

    #26471
    Profile photo of P3DCNC
    P3DCNC
    Participant

    I’m using RC7 from this site. The lines you speak of are in the configuration.h file as well. I also noticed the ability to use Z_Min for the probe.

    Can you post what your probe info looks like in the file ?
    Can I use RC8 from this site or not ?

    Btw, I connected my z-min lines to the touch plate and router bit, did a z home (G28 Z) and that works. FYI.

    #26490
    Profile photo of Martin DB
    Martin DB
    Participant

    G38.* gcodes are implemented in RC8. It’s not recommend yet to go to RC8 with mpcnc.
    I’ve not any configuration, just read in internet. I’ll be trying to use G38.2/3 in the near future, but actually I don’t have nothing implemented or tested.

    #26494
    Profile photo of P3DCNC
    P3DCNC
    Participant

    Ok thanks Martin.

    #26522
    Profile photo of William
    William
    Participant

    This whole Marlin RC8 drama was frustrating enough that I ended up going with an MKS SBASE v1.3 running smoothieware with bCNC.
    Stuff like probing, tool changes, homing spindle just work, no fighting configurations, re-compiling, etc.

    Need to update the configuration? It’s just a text file! Make your change, reset the controller, done. Also, driver current is set by config file entries, no adjusting pots. Pretty cool IMO.

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