Most up-to-date source for BL Touch installation



  • Hi,

    I've found quite a lot of information on installing the BL Touch into a Duet Wifi based printer but it's left me a bit confused as to what the most up-to-date and correct information is.

    Would someone mind pointing me in the right direction?

    I have a new Duet Wifi running 1.2, a 24v psu with no mosfets, buck convertors or expansion Duet boards.

    So with this basic set up which documentation should I be following?



  • https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe#Section_BLTouch

    That works. Recently, M558 was changed to allow a "P9" parameter (instead of the P5 specified in the wiki page I linked) dedicated for BLTouch usage. It's probably easier to set things up with using P9. (Personally, I still use P5, but only because I already jumped through all the hoops to make it work with P5 and I'm too lazy to change it now.)

    Be careful to read the information completely - even the parts that you think might not apply (as they might make reference to something that does.)



  • That's great, thanks @garyd9



  • I forgot to mention: If you want to use that P9 parameter, you'll need to be using the latest (RC4) beta firmware. Personally, I'd suggest using the newer firmware anyway, as it seems pretty stable these days (and resolves some issues that existed in older versions.)



  • OK, ta, and by firmware, we're talking the new board firmware; nothing to do with the BL touch itself..



  • @Drammy:

    OK, ta, and by firmware, we're talking the new board firmware; nothing to do with the BL touch itself..

    Correct. The new duet firmware 1.21. The official release should be right around the corner now if you don't want to use release candidates.



  • Cheers guys



  • Hi all,

    So I'm swapping out my z end stop for a BL touch.

    I've installed and tested the BL touch and all is working as (I think) is expected.

    I'm following the instructions from here and under the Commissioning and Testing section the page reads:

    If all is good It is at this point that you can deploy the probe using the M280 P3 S10 I1 command and slowly lower the nozzle to the bed and find out your own Z trigger height, when the probe touches the bed and the pin retracts you can take a reading of the Z height and use that to input into the G31 command in the config.g file

    I have no Z height as I'm using the probe to set the Z minima, or should I keep the end stop on and use the end stop to determine z minima. Confused..!

    Why do I need to set a z height in G31? Isn't it always going to be 0??


  • administrators

    The G31 Z height is the height of the nozzle above the bed when the Z probe triggers. The firmware needs to know that. See https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe.



  • Ah, of course.

    Any tips for how to set it when I have no z height value? Is there a better way than best-guessing with some digital calipers?



  • When performing a bed execution I get the following error followed by a load of triangle interpolation toast messages…

    [[language]]
    Version: 1.21-RC4
    Message: Uncaught SyntaxError: Unexpected token W in JSON at position 108
    URL: http://192.168.0.9/#
    Line: 3:1
    Error object: {}
    
    

    upon interrogating the response the value shows:

    [[language]]
    Bed equation fits points [60.0, 25.0, 0.062] [60.0, 125.0, 0.317] [175.0, 125.0, 0.400] [175.0, 25.0, 0.202] [100.0, 100.0, 0.293]
    
    Warning: Triangle interpolation: point outside all triangles!
    
    


  • @Drammy:

    Ah, of course.

    Any tips for how to set it when I have no z height value? Is there a better way than best-guessing with some digital calipers?

    It says how to do it in the link David posted, see here - https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height


  • administrators

    @Drammy:

    When performing a bed execution I get the following error followed by a load of triangle interpolation toast messages…

    [[language]]
    Version: 1.21-RC4
    Message: Uncaught SyntaxError: Unexpected token W in JSON at position 108
    URL: http://192.168.0.9/#
    Line: 3:1
    Error object: {}
    
    

    upon interrogating the response the value shows:

    [[language]]
    Bed equation fits points [60.0, 25.0, 0.062] [60.0, 125.0, 0.317] [175.0, 125.0, 0.400] [175.0, 25.0, 0.202] [100.0, 100.0, 0.293]
    
    Warning: Triangle interpolation: point outside all triangles!
    
    

    We recommend mesh bed compensation (G29), not the 5-point bed compensation you are using.


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