Dual Z-Probe Problem 3.1.1



  • Hey.

    I have a problem with my setup. If i use "P8" on the inductive probe and "P5" for the microswitch, Both probes are triggered with the inductive probe, but the microswitch stops working.

    If i reverse it, both probes do work. I think that's very strange.

    RepRapFirmware for Duet 2 WiFi/Ethernet version 3.1.1 running on Duet WiFi 1.02 or later + DueX5
    
    ; Configure Z-Probes
    
    M558 K0 C"zprobe.in"  P8 I0 T18000 F250 H4 A10 S0.005 B0 R0.1
    G31 K0 P1000 X0 Y23 Z4.96
    
    
    M558 K1 C"zstop" P5 I0 F120 H3 T18000 A10 S0.005 B1 R0.2
    G31 K1 P500 X0 Y0 Z0.72 ; Set parameters for z switch (if positive, greater value = lower nozzle. if negative, more negative = higher nozzle)
    


  • Could it be a bug?



  • @JoduWei
    The inductive sensor has different Z distance than the microswitch, so maybe the order makes a difference of activation the two sensors. Another question is why the microswitch is at X0Y0, at the nozzle position.



  • @JoergS5

    @JoergS5 said in Dual Z-Probe Problem 3.1.1:

    @JoduWei
    The inductive sensor has different Z distance than the microswitch, so maybe the order makes a difference of activation the two sensors.

    It is height independent. If i press the switch, nothing happens. If i touch the sensor with metal, both triggered.

    Another question is why the microswitch is at X0Y0, at the nozzle position.

    Because the switch is besides the bed. The nozzle is touching the switch, to set the z-height. So you can switch Toolheads and nozzles without the need to change the z-offset again.

    The inductive probe is just for leveling, z-homing and mesh.



  • => please check David's answer below first before you try my idea

    @JoduWei I have only the idea according to
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M558_in_RepRapFirmware_Num_3
    you may have a NPN inductive sensor and you need an ! "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)."

    And additionally you may need to activate the pullup resistor with ^:
    https://forum.duet3d.com/topic/14209/z-probe-trigger-inverted-after-update-to-rrf3-0/7



  • => please check David's answer below first before you try my idea

    @JoduWei

    https://duet3d.dozuki.com/Wiki/Gcode#Section_M558_in_RepRapFirmware_Num_3

    "Note, if your Z probe is connected to the Z endstop input, in RRF 3.0 on Duet 2 boards only (not in RRF 3.01 and later, and not in RRF 3.0 on Duet 3), that input is by default pre-assigned to be used by the Z endstop, so you must free it up first."

    You could try freeing zstop, although this should be fixed. Or you have the zstop deactivation code still in your config.



  • This post is deleted!

  • administrators

    There is a further limitation that I forgot to mention. There can only be one Z probe of type 1, 2 or 5, it must be connected to the main board, and it must be Z probe number 0.



  • @dc42 it is probe 0. It is on the main board. P5 equal P8?
    Probe 0 can't be configured as P8?

    Like i said

    It works:

    M558 K0 C"zprobe.in"  P5 I0 T18000 F250 H4 A10 S0.005 B0 R0.1
    G31 K0 P1000 X0 Y23 Z4.96
    
    M558 K1 C"zstop" P8 I0 F120 H3 T18000 A10 S0.005 B1 R0.2
    G31 K1 P500 X0 Y0 Z0.72 ; Set parameters for z switch (if positive, greater value = lower nozzle. if negative, more negative = higher nozzle)
    

    It doesnt:

    M558 K0 C"zprobe.in"  P8 I0 T18000 F250 H4 A10 S0.005 B0 R0.1
    G31 K0 P1000 X0 Y23 Z4.96
    
    M558 K1 C"zstop" P5 I0 F120 H3 T18000 A10 S0.005 B1 R0.2
    G31 K1 P500 X0 Y0 Z0.72 ; Set parameters for z switch (if positive, greater value = lower nozzle. if negative, more negative = higher nozzle)
    

    I don't switch the probe, i just swap P5/P8


  • administrators

    Try changing P1000 in your G31 K0 command to P500.


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