Possibilities to adjust the z-offset (without the config.g file)

  • What options are currently available (for me still with RRF 2.05) to read out and also to adjust the current Z offset?

    I build the 3D printer for industrial customers and I cannot give them access to config.g.
    On the one hand for reasons of guarantee and also that the board cannot be integrated into the network (not allowed to integrate this kind of machine).

    So what are the options for reading out and also adjusting the current value for the Z offset?

    In the best case, this should work via the USB interface, since I control the boards with a server (Repetier-Server), which are connected to the Duet via USB (yes I know USB is not recommended, but the customers need this)
    Is there a solution to this?

    It would be really important to find a solution to this.

    Thank you so much!
    Regards Christian (CR-3D)

  • Moderator

    I'm not sure what you mean to ask. If you aren't using config.g you must be providing the Duet with configuration information somehow.

    The Z offset for the probe is configured with G31 at any rate. At some point you must be sending a M558 and G31 to configure the probe, when and how that's sent doesn't matter as long as it's done before the probe is called to action.

  • @CR3D, can you read/write via the USB a small macro file that contains the Z offset (e.g. babysteps)? And then invoke it in config.g.

  • @Phaedrux

    Thanks for your answers. I have a configur.g file and of course the Z-Probe is also tried. Everything works fine. But it is all that is configured, the printer is running and now the board that is configured (because there is no internet, the printer is gone) is gone and you should still feel the Z offset. How would you do it


    That is exactly my question, can I read out the current Z offset via USB and then write and save it again? That would be my wish ...

  • How did you become in the position to commission a printer for a business, presumably for compensation, without the knowledge of how to commission said printer?

    Moreover, how did you not consider the use of the printer before accepting the duty to commission it?

    The Z offset really can be set many ways, permanently or temporarily...

    Have you looked at the list of GCodes in the documentation? https://duet3d.dozuki.com/Wiki/Gcode

  • @bot

    the printers all run flawlessly and i constantly deal with the matter. this special question has arisen again and again in the course of time. I basically know how to adjust the Z offset. For printers with a complete Duet setup, I always do this via the config.g file. However, the special way via USB is unfortunately not known to me. and I unfortunately only have the option of this setup via USB. Is there an option here? Then I would be very grateful for help!

    And yes, I know the GCode list very well!

  • Moderator

    I'm not really sure what you mean. But if you send G31 by itself it will respond with what the currently set value is.

    To measure the current trigger height a macro could be created that prompts the user to jog the nozzle to touch the bed and then uses G30 S-1 to report it to the console, or you can use G30 S-3 in the same way with the difference that it sets the trigger height immediately without having to chnage config.g. That value can be saved to config-override with M500 P31.

  • @Phaedrux Ok thank you!

    Where is the definition of the G30 "S" parameters? i have never read something about "S-3"
    Thank you a lot!

  • Moderator

    I thought you knew the gcode list very well! 😁


  • @Phaedrux

    Oh my mistake! πŸ˜„

    I was there... the general G code overview

    Thanks... I will test it!

  • @CR3D, what you will need is to have the ability to send gcodes over the USB and to retrieve their response, using some script or software. Once you will have that capability, you will have very good control over the printer.

  • @zapta

    Yes I can send Commands and I can receive Messages from the Duet.
    I will test and report πŸ™‚


  • @CR3D You could always implement an adjustable Z=0 endstop... See: https://drmrehorst.blogspot.com/2020/03/a-new-z-axis-optical-endstop-design-for.html

    alt text

  • @Phaedrux

    Ok thank you for your answers...

    I will test it now.

    Must the z offset be configurated in the config.override that i can change it?

    @mrehorstdmd thatΒ΄s not possible, because it is fixed on the toolhead directly

  • @CR3D said in Possibilities to adjust the z-offset (without the config.g file):

    Must the z offset be configurated in the config.override that i can change it?

    if it is in config-overrigde.g that is where you need to update it (as it would otherwise override you do in config.g)

    if its not already in config-override.g it doesn't matter where you put it; but if you intend on using M500 it will be saved to config-override.g

  • @bearer, it is possible to read/write a duet file (e.g. a macro) using the USB/Serial port?

    (If so, any configuration can be saved in a file that is invoked by the standard config.)

  • @zapta haven't tried tbh, but afaik you can use g-code and that shouldn't matter which channel is in use


    (you can't read and parse the file, but ofc executing it should achieve the same thing)

  • Thank you everybody for your help! πŸ™‚

    My solution is following:

    1. Read out my z-offset with G31 via serial command in the console of my server
    2. Change my Z-Offset with G31 Z?.?
    3. Save settings with M500 G31

    This is working well for me πŸ™‚

    Thank you!

  • @bearer

    The M98 command also works via Serial Port. This also would be one solution!

    The M28 command i never tested till yet...

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