"Z probe already triggered at start of move error" message



  • I have just decided to upgrade from firmware 2.03 to 3.0 then to 3.1.1. I have a NPN (NC) Capacitative touch probe installed and had no problems with it working before I upgraded. The black wire is connected to the "Zprobein" pin and the other 2 wires are connected to the power supply.

    I have been trying to get the Z axis to home but keep getting the error message "Z probe already triggered at start of move error" although the bed is far from the probe. I even placed a metal object near the probe to see if the light come on and goes off and that worked fine. When I issue the G30 command the error message also appears.

    I tried going through config.g to figure out what the issue is and I hate to say it but I am stuck.
    Here is my homez.g configuration:

    ; homez.g
    ; called to home the Z axis
    ;
    ; generated by RepRapFirmware Configuration Tool v2 on Wed Jul 03 2019 21:11:39 GMT+0100 (British Summer Time)
    ;
    G91 ; relative positioning
    G1 H1 X-535 F3000 ; move quickly to X axis endstop and stop there (first pass)
    G1 X5 F6000 ; go back a few mm on X axis
    G1 H1 X-535 F300 ; move slowly to X axis endstop once more (second pass)
    G90 ; absolute positioning
    G91 ; relative positioning
    G1 H1 Y-465 F2000 ; move quickly to Y axis endstop and stop there (first pass)
    G1 Y5 F6000 ; go back a few mm
    G1 H1 Y-465 F300 ; move slowly to Y axis endstop once more (second pass)
    G90 ; absolute positioning
    G1 X265 F3000 ; move to centre of X
    G1 Y230 F2000 ; move to centre of Y
    G30 F1000 ; home Z by probing the bed. Stop when probe triggered and set Z trigger height.
    G90 ; absolute positioning
    G91 ; relative positioning
    G1 H2 Z0.2 F100 ; lift Z relative to current position. Ignore endstops whilst moving (S2).
    G90 ; absolute positioning
    G1 Z0.25 F100 ; Move the z axis to be 0.25mm from the bed

    I haven't yet completed all my config.g yet but my setup so far is like this:
    ;Kinematics type
    M669 K0 ; Set kinematic movements as Cartesian
    ;*************************************************************************************************
    ;****************** Drives Movement Direction***********************************************
    ;*************************************************************************************************
    M569 P0 S1 ; X axis motor physical drive 0 goes forwards
    M569 P1 S1 ; Y axis motor physical drive 1 goes forwards and controls 1 of 2 motors
    M569 P3 S1 ; E0 (Extruder 0) motor physical drive 3 goes backwards
    M569 P5 S0 ; E2 motor on duex5 physical drive 5 goes forwards and also controls 1 of 4 Z motors
    M569 P6 S0 ; E3 motor on duex5 physical drive 6 goes forwards and also controls 1 of 4 Z motors
    M569 P7 S0 ; E4 motor on duex5 physical drive 7 goes forwards and also controls 1 of 4 Z motors
    M569 P8 S0 ; E5 (Y) axis motor on duex 5 physical drive 8 goes backwards and controls the second Y motor
    M569 P9 S0 ; E6 motor on duex5 physical drive 9 goes forwards
    ;*************************************************************************************************
    ;**************** DRIVE MAPPING******************************************************************* ;*************************************************************************************************
    M584 X0 Y1:8 Z5:6:7:9 E3 ; Drive 0 controls X, drive 1 & 8 controls Y, drive 2a/2b & 9 controls Z, drives 3 controls extruder 0 (dyzend)
    ;*************************************************************************************************
    ;**************** DRIVE STEPS/MM *****************************************************************
    ;*************************************************************************************************
    M350 X16 Y16 Z16 E16 I1 ; Configure 16x micro-stepping with interpolation to 256x for X,Y,Z motors.
    M92 X214.81 Y79.21 Z400.04 ; Set steps/mm for X,Y,Z motors.
    M92 E642.22 ; Set steps/mm for Extruder motor.
    G21 ; Work in millimeters
    ;*************************************************************************************************
    ;**************** DRIVE SPEEDS***********************************************************
    ;*************************************************************************************************
    M566 X900.00 Y900.00 Z300.00 E300.00 ; Set maximum instantaneous speed changes (mm/min)
    M203 X10000.00 Y10000.00 Z500.00 E2000.00 ; Set maximum speeds (mm/min)
    M204 P540 T2700 ; Set print speed to 540 mm/s and travel speed to 2700 mm/s.
    M201 X10000.00 Y10000.00 Z3600.00 E3600.00 ; Set accelerations (mm/s^2)
    M593 F80 ; Set dynamic acceleration adjustment to 80Hz
    ;*************************************************************************************************
    ;**************** DRIVE CURRENT****************************************
    ;*************************************************************************************************
    M906 X2000 Y2000:2000 Z1000:1000:1000:1000 E640 I80 ; Set motor currents (mA) and motor idle factor in %
    M84 S60 ; Set idle timeout
    ;*************************************************************************************************
    ;*************** AXIS LIMITS*****************************************************************
    ;*************************************************************************************************
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X530 Y460 Z443.7 S0 ; Set axis maxima
    ;*************************************************************************************************
    ;ENDSTOPS********************************************************
    ;*************************************************************************************************
    M574 X1 S1 P"!xstop" ; X min active low endstop switch
    M574 Y1 S1 P"!ystop" ; Y min active low endstop switch
    M574 Z1 S2 ; Z min switch controlled by probe
    ;*************************************************************************************************
    ;FILAMENT MONITORING*******************************************
    ;*************************************************************************************************
    M591 D0:1 C"e0_stop" P2 S1 ; Use endstop 3 for the filament sensors for drives 0 & 1.
    ;*************************************************************************************************
    ;Z Probe*************************
    ;*************************************************************************************************
    M558 P5 C"^zprobe.in" H3 F500 T6000 A3 ; Set Z probe type (P5 NC) to switch, the dive height (3mm), dive speed (500mm/min) + speed of travel to probe coordinates (6000mm/min).
    G31 P1000 Z0.882 ; Set Z probe trigger value, offset and trigger height
    M557 X0:530 Y0:460 R19 P30 ; Define mesh grid co-ordinates with X axes separated by 120mm, Y axes separated by 88mm, probe radius = 9mm and 30 probe points (max 32 probe points).
    M671 X550:-40:90:460 Y-100:-100:385:385 ; Z axis leadscrews are at X-40:Y-100, X550:Y-100, X90:Y385 and X460:Y385.
    ;
    ;*************************************************************************************************

    Can you spot where I am going wrong here?



  • @dawgheart said in "Z probe already triggered at start of move error" message:

    M558 P5 C"^zprobe.in" H3 F500 T6000 A3 ;

    when defining M558, I would try the information:

    • Invert the input by prefixing the input pin (C parameter) with ! character, when using an NPN output inductive or capacitive sensor or using an NO switch (not recommended, use a NC switch instead).
    • The pullup resistor on the Z probe input is disabled by default. Enable it by prefixing the input pin (C parameter) with the ^ character. Enable pullup resistor with ^ if using Duet 2, running RRF3, using the Z probe input pin, and the probe type is a switch or BLTouch.

    from https://duet3d.dozuki.com/Wiki/Gcode#Section_M558_Set_Z_probe_type

    so adding ! and probably removing the ^



  • Hi JoergSS,

    Thank you for that clarification which initially misinterpreted. Your solution seems to have resolved my issue but I've also found out that 1 of 4 Z motors is not working. So I haven't been able to home Z as yet. I will solve this and let you know the outcome of the z homing.

    kind regards.



  • @dawgheart Thanks for confirmation. Please tell if you need help with the motors.


  • Moderator

    @dawgheart said in "Z probe already triggered at start of move error" message:

    G31 P1000 Z0.882

    Your G31 needs an X and Y offset for the probe from the nozzle.

    @dawgheart said in "Z probe already triggered at start of move error" message:

    G30 F1000 ;

    G30 does not take a feed rate. To set the speed before probing you can send an M558 F1000 to set the dive speed.



  • Thank you all...I have made those recommended changes above and have managed to solve my motor problem. Turns out, it was an imbalanced bed that was causing the issue.

    So all my endstops and probe are now working fine but I can't see the filament sensor under "Machine Specific" in the web control. I have tested the sensor and it seems to be fine. Am I being paranoid? PSB filament sensor config.

    M591 S1 P1 C"e0_stop" ; Use endstop 3 for the filament sensors for drives 0.


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