Probing grid



  • @exerqtor said in Probing grid:

    M208 X328 Y323 Z390 S0 ; Set axis maximal

    328 - 38 = 290



  • Haha, i just meassured the Z-probe offset again, and it's time for me to take a break or somehting.

    The correct offeset it X38 Y-1.2 😆 Think it's beer-o'clock now.

    And i've put M208 to X338 in the printer btw, forgot to say that later.

    But i think i read somewhere in the Dozuki that probing points is allowed outside the max/min?



  • Ok so now i srsly can't understand carp.

    I've reconfigrued the config.g to this:

    M574 Z1 S2                             ; Set endstops controlled by probe
    M307 H7 A-1 C-1 D-1                    ; Disable heater on PWM channel for BLTouch
    M558 P9 H5 F600 T7200 S0.05 B1 R0.1 A5 ; Set Z probe type to BLTouch, dive height,
    G31 P287 X38.2 Y-1.2 Z1.5              ; Set Z probe trigger value, offset and trigger height
    M280 P7 S150                           ; Set Logic voltage Free Zmin (3.3V)
    M557 X43:338 Y4:323 S45                ; Define probing grid
    

    And what happens now when the printer is homed on all axis is that the probe moves so slow to the first probing spot that the bed catches up and it rams the printhead.

    If i first home all axis, send Z to 390 and then issue G29 the bed hotend/probe just snailpace out and the bed catches up with it. So i have to do an Emergency stop.

    Then i tried homing all axis, move the probe/printhad to X43 Y 4. With the bed at Z 380, and when i issue G29 it start snailpacing the printhead backwards to home position while the bed meets up??

    Like i initialy said, i can't understand how this is meant to work at this point.



  • post your homeall.g



  • @veti said in Probing grid:

    post your homeall.g

    I updated the previous post just 1 second after your reply btw!

    Here is my homeall.g

    G91                     ; Relative positioning
    G1 Z3 F2000 S2          ; Lower Z(bed) 3mm relative to current position
    G1 S1 X-341 Y-354 F3000 ; Move quickly to X or Y endstop and stop there (first pass/coarse home)
    G1 S1 X-341             ; Home X axis
    G1 S1 Y-354             ; Home Y axis
    G1 X5 Y5 F2000          ; Go back a few mm
    G1 S1 X-341 F360        ; Move slowly to X axis endstop once more (second pass/fine home)
    G1 S1 Y-354             ; Then move slowly to Y axis endstop (second pass/fine home)
    G90                     ; Absolute positioning
    G1 X44 Y5 F3500         ; Go to first bed probe point and home Z
    G30                     ; Home Z by probing the bed
    G1 S1 X-341             ; Home X axis
    G1 S1 Y-354             ; Home Y axis
    G90                     ; Absolute positioning
    G1 Z5 F6000             ; Lower Z(bed) 5mm from Nozzle
    

    When i'm sitting here pulling my hair out i start thinking, i haven't got the X/Y offset inverted?

    Like it should be G31 P287 X-38.2 Y1.2 Z1.5 ??

    The probe is to closer to X0 than the nozzle and farther away from Y0 than the nozzle.



  • @exerqtor said in Probing grid:

    Like it should be G31 P287 X-38.2 Y1.2 Z1.5 ??

    - if to the left of hotend + to the right

    also in your homing script you dont need anything after G30



  • @veti

    Yeah then X-38.2 and Y1.2 should be correct shouldn't it?

    If i want to move the printhead away from the printhead after homing Z i do have to have something after G30. Which i do 😛



  • @exerqtor said in Probing grid:

    Yeah then X-38.2 and Y1.2 should be correct shouldn't it?

    kind of hard to tell without a picture.



  • Have to do that tomorrow, if i don't walk away from the printer now shit might start hitting the
    fan.

    But, to put it this way: When i move the printer to X43.2 Y3.8 the probe is 5mm from the edge in both directions.



  • Refering to the G31 section in the Dozuki:

    "X and Y offsets of the Z probe relative to the print head (i.e. the position when the empty tool is selected) can be specified. This allows you to calculate your probe coordinates based on the geometry of the bed, without having to correct them for Z probe X and Y offset.".

    If i understand correct this means that with the G31 setup correct and the printer have room for the movement, that the firmware will compensate for the z-probe offset. Right?

    So if i put X5 Y5 in the M557 first PROBE spot ie. the PROBE position, not the nozzle wil be 5:5? In that case it must be a bug somewhere, because thats not my printers doing at all.


  • Moderator

    I'm not exactly sure how it's supposed to work but for my grid I choose the x y coordinates of where the probe can reach, not the nozzle.



  • @phaedrux
    Yeah i have no problem with that being the way it should work either, but if i define x43.2:305.2 Y3.8:321.8 in M557 it still don't move hotend to that spot before it starts the probing (like i mention farther up it just moves in a snailspace outwards and the bed crashes in the hotend).

    So somethings either bugged in the firmware, or i have an error or something conflicting in my codes somewhere 🤮


  • Moderator

    That's definitely odd sounding behavior for the mesh compensation. How are you starting the g29?
    If you switch back to 2.02 does it behave the same ?


  • administrators

    @exerqtor said in Probing grid:

    But i think i read somewhere in the Dozuki that probing points is allowed outside the max/min?

    Probing using G30 commands (for example, in bed.g for delta calibration or true bed levelling) outside the area defined by M208 is allowed. Grid probing is constrained to keep the head reference point within the M208 area.


  • administrators

    @exerqtor said in Probing grid:

    So if i put X5 Y5 in the M557 first PROBE spot ie. the PROBE position, not the nozzle wil be 5:5?

    Yes.



  • @dc42 said in Probing grid:

    @exerqtor said in Probing grid:

    But i think i read somewhere in the Dozuki that probing points is allowed outside the max/min?

    Probing using G30 commands (for example, in bed.g for delta calibration or true bed levelling) outside the area defined by M208 is allowed. Grid probing is constrained to keep the head reference point within the M208 area.

    @dc42 said in Probing grid:

    @exerqtor said in Probing grid:

    So if i put X5 Y5 in the M557 first PROBE spot ie. the PROBE position, not the nozzle wil be 5:5?

    Yes.

    Ok that's fine, so with this code:

    M208 X-8 Y-21 Z0 S1             
    M208 X338 Y323 Z390 S0
    G31 P287 X-38 Y1 Z1.5 
    M557 P5:5 X5:300 Y5:318
    

    the BLTouch pin should start at 5:5 and end at 300:318 with 5 probes in each direction am i correct?

    And if the machine is freshly homed on all axes(in my case putting the nozzle at X-8 Y-21 Z5), the printhead/probe should move out to the correct X/Y position before deploying the probe and starting to raise the bed?

    ;
    Ok so i just reviewed my config.g from yesterday. And the only changes i made was to change the M557 by adding the P parameter and ditching the S. And now it all works for some strange reason.


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