CNC tool length measurement on Z-Axis

Hi @all,

i am using repetier firemware for my cnc machine.
I was planing on using a tool length measurement end stop.

Basicly it is an endstop that activates somewhere above my worktable.
Something like this

The question is how to configure this?

The behaviour I would need is:

* Home Z in negative direction against Z-Min-Endstop
* Stop When hitting endpoint
* set absolut coordinates of repetier controler to tool length sensor height(e.g. 18mm), instead of setting it to zero

Is there any way? 


  • See G30 description in Repetier.ino file. You can use it to level Z and setting offsets. That was added to allow CNC tools to level to object height or wherever they have their sensor. So it sets the physical z=0 and adjust z to what you need at once.
  • Thanks that was the hint I needed. It took me a while to figure it out.
    This is how I solved my Problem.

    Feature Configuration:

    #define FEATURE_Z_PROBE 1 //this feature needs to be enabled to use commands G30
    #define Z_PROBE_HEIGHT 26   //because my switch has a height of 26mm when its triggered

    Also the defines
    should be configured.

    This is my Setup:
             | |
             | |                         <- end mill
             | |
             |S|                        <- The S is my Z_Probe (switch for messuring my tool hight)
          |         |                    <- this is the workpiece i want to mill down
    ###############  <- This is by Bed, lowes Point my tool can reach.

    The workpiece is placed on the bed and the switch is placed on the workpiece.
    The end mill is then probed onto the switch with the following command.

    G30 H<workpiece height> R0

    Result if my Workpiece has a height of 10mm

             | |
             | |
             | |
             __                        <- This is :   Machine(36) = Display Position(26) = Machine(36) + Offset(-10)
         +-------+                  <- This is:    Machine(10) = Display Position(0) = Machine(10) + Offset (-10)
          |         |
    ##############   <- This is:     Machine(0) = Display Position(-10) = Machine(0)+ Offset(-10)

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