Probing starts too high?

  • Hi. I have a bewildering problem.

    Litterally 2 hours ago, i pressed print, the machine did its autocalibration and printed just fine.

    I went to print the same exact thing a second time, but now the probing starts at around z = 26 as displayed in the duet portal….. WHY? I changed nothing. I just pressed print again. I've never had this issue before. I've tried to reset the printer using the HARD STOP button on the portal, but no dice... it doesn't appear like the steppers are skipping steps. I am running a delta....

    config.g shows approximately the correct bed height, and if i home, then go down to z=0 that is correct... it just starts probing too high. (resulting in a failed autocal).


    Firmware Name: RepRapFirmware for Duet WiFi
    Firmware Electronics: Duet WiFi 1.0
    Firmware Version: 1.17e (2017-02-10)
    WiFi Server Version: 1.03 (ch fork)
    Web Interface Version: 1.14a


    But again, i made zero changes since two hours ago when it was printing great.

    ; Auto calibration routine for delta printers
    ; Before running this, you should have set up your zprobe Z offset to suit your build, in the G31 command in config.g.
    M561						; clear any bed transform, otherwise homing may be at the wrong height
    G31 X0 Y0					; don't want any probe offset for this
    G28							; home the printer
    ;*** Remove the following line if your Z probe does not need to be deployed
    ;M98 Pdeployprobe.g			; deploy the mechanical Z probe
    ; The first time the mechanical probe is used after deployment, it gives slightly different results.
    ; So do an extra dummy probe here. The value stored gets overwritten later. You can remove this if you use an IR probe.
    ;G30 P0 X0 Y0 Z-99999
    ; Probe the bed and do 6- or 7-factor auto calibration
    G30 P0 X0.00 Y110.00 Z-99999 H-0.12
    G30 P1 X70.71 Y84.26 Z-99999 H-0.08
    G30 P2 X108.33 Y19.10 Z-99999 H0.26
    G30 P3 X95.26 Y-55.00 Z-99999 H0.32
    G30 P4 X37.62 Y-103.37 Z-99999 H-0.04
    G30 P5 X-37.62 Y-103.37 Z-99999 H-.28
    G30 P6 X-95.26 Y-55.00 Z-99999 H-.17
    G30 P7 X-108.33 Y19.10 Z-99999 H-.28
    G30 P8 X-70.71 Y84.26 Z-99999 H-.33
    G30 P9 X0.00 Y55.00 Z-99999 H-0.14
    G30 P10 X47.63 Y27.50 Z-99999 H-0.1
    G30 P11 X47.63 Y-27.50 Z-99999 H-0.18
    G30 P12 X0.00 Y-55.00 Z-99999 H-0.02
    G30 P13 X-47.63 Y-27.50 Z-99999 H0.02
    G30 P14 X-47.63 Y27.50 Z-99999 H-0.48
    G30 P15 X0 Y0 Z-99999 S6
    ;*** Remove the following line if your Z probe does not need to be retracted
    M98 Pretractprobe.g				; retract the mechanical Z probe
    G1 X0 Y0 Z150 F15000			; get the head out of the way of the bed
    ;M557 R120 S15
    ;G29 S1

  • administrators

    The only reason I can think of why it would start probing much too high even though it has the Z height about right is if the trigger height in the G31 command has got set too high. Run M558 to check what type of Z probe you have configured, then run G31 T#, where # is the Z probe type, to see what trigger height is set.

  • M558
    Z Probe type 1, invert no, dive height 5.0mm, probe speed 120mm/min, travel speed 6000mm/min, recovery time 0.00 sec, used for axes:

    9:17:41 PMG31 T1
    Threshold 500, trigger height 21.82, offsets X0.0 Y0.0

    So. I guess that solves that mystery.. I just checked my config.g file and sure enough 21.82 was set there instead of 1.82.. I didnt change it in between prints though (but maybe several prints before that)….. strange. Barring end-user incompetence, what could it be?!

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