Adding a „script“ in Homing process

Hey all of you,

since I‘m using a button / switch between the bed and the nozzle for z homing I‘m looking for a way to get to Z=0 in the homing process. 
Right now I‘m using 0.92 and have a starting script in the beginning of every gcode that moves the bed down, homes, moves the head aside and then moves the bed up to printing height (below 0 in the z axis)
This results in negative z values shown everywhere which I don’t mind so much but isn’t nice.

Waht I’d love to have is a sort of script not embedded in the gcode but the firmware so nothing happens when using the wrong gcode.
1.0.x has the feature to move the bed down before homing but with this version I can’t move below 0 in the z axis. I assume there is an option to turn this behaviour on and off?

Is there a way to implement the print head moving aside after touching the switch and then moving the bed up as part of homing so the z koordinates are right and there is no way to forget the right script at the start of a print file? 
(Sending G92 Z0 at the end of my script does not do the trick.


  • So your button is higher then the bed?

    I understand that this is a problem. Solution would be to treat is a z probe. Z-probes also trigger before bed is reached and firmware uses z probe height to compensate the error. So set z probe to same pin, homing order with temperature, make bed go down enough and home order x, y then go to defined position (which is why you need that order) and measure z. Problem is now z probe normally gets deactivated and you can move bed up. In your case you will have the button there. So you might need to modify the homing process a bit. Currently not sure about the correct order. I know in my case it goes back to xy home pos. If z changes then it would be ok. But be aware when testing that it might do it at wrong point. So use slow homing speed for testing so you can react on it.
  • Repetier said:
    So your button is higher then the bed?

    I just read through the Z-Probing "manual" and got the idea behind it. I assume it will take me some time to understand it in detail and get it to work, but I'll definitely try as soon as possible. 

    Maybe I'll get back to you with another few questions.  :D
    But for now thank you for "planting" the idea how to do it.

  • I did manage to basically set it all up, but what I did not manage is the printer not driving into the switch. 
    It moves the bed down, homes X, then Y, and then Z (at X=0 and Y=0) but after switching the button (twice) it goes down "into" the button and i can't get it to move to another point before moving the bed up to Z=0
    what am I doing wrong?
  • What is bed down for you? Closer to extruder or away?

    > but after switching the button (twice)
    you mean the homing with retry?
    > it goes down "into" the button and
    You mean below button on bed height?
    > i can't get it to move to another point before moving the bed up to Z=0
    where does it think z=0 is? Sounds like you move below 0 what makes no sense. Homing z will assume z = z min position.

    At the end it will move to z=0. How does it move here related to the raised button problem?

    Which firmware are you now using and which settings for z probe.
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