Z MAX HOMING - Auto bed leveling

I have setup auto bed leveling. Per the instructions it recommends homing to Z MAX. I have installed an endstop on top and have enabled it in firmware. When i manually home z through the repetier host software it does the following.

1. it goes up touched the endstop
2. backs off to the distance that i specified
3. then it goes back touches the endstop again
4. then goes all the way down and crashes into the bed --(of course i am not expecting this behavior)--

 I think that i am missing a configuration point in the header file but not sure which. Can someone give me clear instructions on getting Z MAX homing to work correctly? I am using the repetier firmware and the repetier host software on a prusa style cartesian printer nothing special.


  • Are you on dev version?
    See what


    is set to. This is the target z after z homing and if that is set 0 it would go down. If z length is a bit to big that means crashing into the bed. Should be a bit less then z height.

  • edited December 2017
    No. Im not on the dev version. I think i figured out what is going on.

    After I home Z it goes to a specified distance to then heat the hotend. Well I have it set to go to 30.

    #define ZHOME_HEAT_ALL 1
    #define ZHOME_HEAT_HEIGHT 30

    For some reason or another it thinks Z=0 is about 50mm under the bed. So in order for me to keep it from wanting to go through the bed I have to set that number really high. Right now I have it set to 60 and its only about 5mm above the bed. So its not a Z MAX Homing situation at all i guess. The printer doesnt know where Z=0 is. After it heats the hotend it homes to Z again then crashes once more because I have the Z_PROBE_BED_DISTANCE set to 10. So I have to set that number high also.
  • Should I try the dev version? Because Im struggling to get everything working consistently and repeatable.
  • Yes, dev version is very short before becoming final 1.0 and has better z probing (less errors).
  • Where do I find the dev version for download?
  • https://www.repetier.com/firmware/dev/

    is the config tool for it. Or on github selecting dev branch.
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