G30 homing issues with capacitive NPN Sensor



  • Hello,

    I really need HELP.

    I replaced my IR sensor with an capacitive sensor and when using G30 befor any homing the sensor stopps perfectly above the heatbed like calibrated.
    but as soon I am homing X or Y or using G30 in a script the G30 is not stopping and drives into the heatbed.

    Any Idea?

    here are my config files:

    ; Configuration file for RepRap Mendel 3
    ; RepRapPro Ltd
    ;
    ; Copy this file to config.g if you have a Mendel 3
    ; If you are updating a config.g that you already have you
    ; may wish to go through it and this file checking what you
    ; want to keep from your old file.
    ;
    M111 S0 ; Debug off
    M550 PRepRapPro Mendel 3 ; Machine name (can be anything you like)
    M551 Preprap ; Machine password (currently not used)
    M540 P0xBE:0xEF:0xDE:0xAD:0xFE:0x14 ; MAC Address
    M552 P192.168.1.14 ; IP address
    M553 P255.255.255.0 ; Netmask
    M554 P192.168.1.1 ; Gateway
    M555 P2 ; Set output to look like Marlin
    G21 ; Work in millimetres
    G90 ; Send absolute corrdinates…
    M83 ; ...but relative extruder moves
    M558 P4 Y0 X0 Z1 I1 ; Use a capacitive NPN Z probe
    M574 X1 Y1 ; set endstop configuration (Y endstop only, at low end, active high)
    G31 Z0.1 P800 ; Set the probe height and threshold (deliberately too high to avoid bed crashes on initial setup)
    M906 X800 Y1000 Z800 E800 ; Set motor currents (mA)
    ;M305 P0 R4700 H0 L0 ; Set the heated bed thermistor series resistor to 4K7
    ;M305 P1 R4700 H0 L0 ; Set the hot end thermistor series resistor to 4K7
    ;M305 P2 R4700 H0 L0 ; Set the hot end thermistor series resistor to 4K7
    M569 P0 S1 ; Reverse the X axis
    M569 P3 S0 ; Reverse the Z axis
    M92 E660:660:660 ; Set extruder steps per mm
    G31 Z0.1 P600 ; Set the probe height and threshold (deliberately too high to avoid bed crashes on initial setup)
    M556 S78 X0 Y0 Z0 ; Put your axis compensation here
    M201 X3000 Y3000 Z150 E500 ; Accelerations (mm/s^2)
    M203 X15000 Y15000 Z100 E3600 ; Maximum speeds (mm/min)
    M566 X200 Y200 Z30 E20 ; Minimum speeds mm/minute
    M208 X-8 S1 ; Set axis minimum (adjust to make X=0 the edge of the bed)
    M208 X214 Y210 ; Set axis maxima (adjust to suit your machine)
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 S-273 R-273 ; Set tool 0 operating and standby temperatures


    homez.g is:

    G91
    G1 Z5 F2000
    G90
    G1 X52 Y22
    G30
    G1 Z0 F1000




  • You could add H5 to your M558 command to set a height of 5mm before probing, also try probing at a lower speed.


  • administrators

    I can't think of any reason why homing X or Y should make a difference to whether the capacitive sensor triggers or not, provided that the sensor is over the same point of the bed in both cases.

    Does your capacitive sensor trigger reliably everywhere on the bed, and whether the bed is hot or cold? Capacitive sensors are susceptible to temperature, humidity and bed surface changes, so I advise against them.



  • The sensor is triggering correct.
    the sensor LED lights up, but the z move doesn't stop,
    i will come back with more info on sunday when I am back at my printer



  • Adding M558 P4 to homez.g solved my problem


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