No 3.3V with bltouch



  • I have followed the wiki for the wiring of bltouch smart on Duet 2 wifi 1.04 with latest firmware. If I connect the bltouch z output to the z probe connector and switch on the board, the 3.3V led don't light up. Same behavior after cut the trace on bltouch for 3.3V logic. The bltouch has no issue before on ramps. It's a genuine bltouch.


  • administrators

    @pipersw, it sounds to me that you have used the wrong pins on the Z probe connector, because when you connect the BLTouch you are shorting the +3.3V pin on the Z probe connector to ground.



  • Is this what you followed?

    https://duet3d.dozuki.com/Wiki/Connecting_a_Z_probe

    I've run into people who had a bad connection at the plug on the BLTouch itself. The wires are pretty delicate.

    Try checking all the wires for continuity with a multimeter.



  • I have done the following wiring. Red wire for Z probe output is connected to white wire.
    https://photos.app.goo.gl/bKdUWafcFMTXi5n67



  • Wrong wiring ! I reverse two wire and now the bltouch selftest at duet boot.
    Now when I home z the bltouch not deploy. I investigate.
    I put signal on pin 8 heater 3, but the wizard print in config files heater 4, it is good ?



  • @pipersw I don't understand what you mean. Can you show the gcodes you mean?



  • I follow the guide here for connection : I use heater 3 pin 8 on Duet2Wifi 1.04 with firmware 2.02

    At power up, the bltouch is red with a selftest (deploy and retract).
    When I use macro for deploy and retract, nothing happen, and if I home Z, the bltouch don't deploy.

    config.g:
    ; Endstops
    M574 X1 Y1 S0 ; Set active low and disabled endstops

    ; Z-Probe
    M574 Z1 S2 ; Set endstops controlled by probe
    M307 H3 A-1 C-1 D-1 ; Disable heater 3 on PWM channel for BLTouch
    M558 P9 H5 F120 T6000 ; Set Z probe type to bltouch and the dive height + speeds
    G31 P25 X-26 Y-40 Z0 ; Set Z probe trigger value, offset and trigger height
    M557 X20:200 Y20:200 S40 ; Define mesh grid

    deployprobe.g:
    M280 P3 S10 I1

    retractprobe.g:
    M280 P3 S90 I1



  • what version of the bltouch do you have?
    apparently there is a new 3.0 version which is not compatible with the 2.0 commands.



  • I have the smart 2.0 bltouch


  • administrators

    Check that you don't have another M307 H3 command in config-override.g.



  • I don't have a config-override.g file. I progress, home all works, I have just the mesh with the probe outside the bed despite of M557 in config.g

    config.g:
    ; Axis Limits
    M208 X-34 Y0 Z0 S1 ; Set axis minima
    M208 X220 Y215 Z240 S0 ; Set axis maxima

    ; Z-Probe
    M574 Z1 S2 ; Set endstops controlled by probe
    M307 H3 A-1 C-1 D-1 ; Disable heater 3 on PWM channel for BLTouch
    M558 P9 H5 F120 T6000 ; Set Z probe type to bltouch and the dive height + speeds
    G31 P25 X-26 Y35 Z1.740 ; Set Z probe trigger value, offset and trigger height
    M557 X30:220 Y45:215 S40 ; Define mesh grid



  • I have to take in account the probe offset in M557, so I will try
    M557 X30:220 Y40:180 S40


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