Issues with heightmap



  • Hello there!

    Been trying to get my bed fully leveled and have faced some issues with the heightmap generated after running G29. The heightmap is displaying too high up on the graph. It shows correctly if I set the Z probe offset to 2.5, but the actual Z probe offset is 1.7. At 1.7 the heightmap turns out like this:

    https://imgur.com/a/6bQwM

    I am using a BLTouch a the Z Probe.

    Am I missing something here?


  • administrators

    How do you Z-home your printer: using the Z probe, or using an endstop switch? Please share your homing files.



  • Is your Homing X and Y-Axes set to one of the probed points?

    If not, i would advice to set it to one of the points.



  • @dc42:

    How do you Z-home your printer: using the Z probe, or using an endstop switch? Please share your homing files.

    I home with the probe.

    [[language]]
    ; homeall.g
    ; called to home all axes
    ;
    ; generated by RepRapFirmware Configuration Tool on Wed Oct 25 2017 13:35:35 GMT+0200 (Vest-Europa (sommertid))
    
    ; Relative positioning
    G91
    
    ; Lift Z
    G1 Z5 F6000
    
    ; Course home X or Y
    G1 X-295 Y-295 F1800 S1
    ; Course home X
    G1 X-295 S1
    ; Course home Y
    G1 Y-295 S1
    
    ; Move away from the endstops
    G1 X5 Y5 F6000
    
    ; Fine home X
    G1 X-295 F360 S1
    ; Fine home Y
    G1 Y-295 S1
    
    M98 Pdeployprobe.g
    
    ; Move Z down until the switch triggers
    G1 Z-295 F1800 S1
    
    ; Absolute positioning
    G90
    
    ; Tell the firmware where we are
    G92 Z2.5
    
    M98 Pretractprobe.g
    
    ; Uncomment the following line to lift the nozzle after probing
    G1 Z5 F100
    
    

    I have set the offset to 1.51 now which makes enough room to start printing. 1.7 offset and the nozzle touches the bed at 0.

    @MoS-tekknix:

    Is your Homing X and Y-Axes set to one of the probed points?

    If not, i would advice to set it to one of the points.

    Its not, its moving about 15xy in from the homing point. Would it make a big diffrence?

    Edit: Ugh, after uploading the homing file I belive I see the issue. "G92 Z2.5" - will change it once im done with the current print!



  • I've noticed the same (even my bed is leveled enough) if the Homing-Point was a different one as the Probing-Points.

    Give it a try



  • @MoS-tekknix:

    I've noticed the same (even my bed is leveled enough) if the Homing-Point was a different one as the Probing-Points.

    Give it a try

    Will do! I belive the issue is due to the "G92 Z2.5" in my homing file. Going to change it once im done with the current print 🙂



  • Been playing around with the values today, but I can't seem to get it right.

    If I uncomment the G92 command the heightmap turns up below the grid.

    If I dont have any G92 set and a Z probe offset on 1.7 then the nozzle should be at Z0 when it starts printing? That is if the offset from the probe and nozzle is 1.7.


  • administrators

    The G92 Z command should only be used if you are homing with a Z-min endstop switch. The Z parameter should be the distance between the nozzle and the bed at which the bed stops when the G1 S1 Z-xxx command in homez.g or homeall.g is executed. You must use the same value in homeall.g and homez.g, unless homeall.g calls homez.g to do Z homing.



  • @dc42:

    The G92 Z command should only be used if you are homing with a Z-min endstop switch. The Z parameter should be the distance between the nozzle and the bed at which the bed stops when the G1 S1 Z-xxx command in homez.g or homeall.g is executed. You must use the same value in homeall.g and homez.g, unless homeall.g calls homez.g to do Z homing.

    Cheers, got it all working now!


Locked
 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.