Automatic Tool Z-Offset Correction



  • Hi,

    i want to use a "Tool Height Probe" (mechanical switch like in the picture below) to detect the actual Nozzle height for different tools at one 3D-Printer at a certain Temperature.
    I thought one possibillity to achive this is to override the Z-Offset in the config.g file at the selectet Tool.
    I would like to use G-Code Meta Commands: https://duet3d.dozuki.com/Wiki/GCode_Meta_Commands
    But im not sure if it is possible, because variable declaration and assignment is not implementet yet.

    Also i would like to know if ther is another posibility to change the Tool Z-Offset without going into the config.g file and the need to restar the firmware.

    I use:
    Toolchanger (4 Tools)
    BL-Touch (Mesh bed compensation)
    Duet2 Ethernet Board
    Firmware 3.1.1Toolheightsensor.jpg

    I would be glad if you guys have some thoughts on this projekt. Also maybe there is someone who already implemented such system into a 3D-Printer or have a differernt way to achive it.


  • administrators

    @Philipp-R said in Automatic Tool Z-Offset Correction:

    i want to use a "Tool Height Probe" (mechanical switch like in the picture below) to detect the actual Nozzle height for different tools at one 3D-Printer at a certain Temperature.
    I thought one possibillity to achive this is to override the Z-Offset in the config.g file at the selectet Tool.
    I would like to use G-Code Meta Commands: https://duet3d.dozuki.com/Wiki/GCode_Meta_Commands
    But im not sure if it is possible, because variable declaration and assignment is not implementet yet.
    Also i would like to know if ther is another posibility to change the Tool Z-Offset without going into the config.g file and the need to restar the firmware.

    Yes it's possible, and you don't need to use variables. The G10 command sets the trigger height, and object model variable sensors.probes[N].lastStopHeight will return the height at which the probe last triggered.



  • @dc42 is that line in the object model also applicable to G38.2 moves?



  • @dc42 thank you for the quick answer.
    Do i have to configure also the "Tool Heigt Probe" like the BL-Touch in the config.g with the M558 and G10 command.

    What i don't understand is were do i have to change the the Tool Z-Offset? directly in the config.g file or do i have override the value bevor printing?

    It would be great if you have more detailed information about this problem or also when tere is a thread who already a discussion is been made. Unfortunately i diddn't found the right information in the forum.



  • By the way i have found one thread about this topic: https://forum.duet3d.com/topic/18942/calculating-tool-offset-cnc/3?_=1604994474624


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