BLTouch not triggering, LED on BLTouch working

  • I have wired up a BLTouch as a Z-probe for my delta printer (see picture). I have cut the strip connecting the two pads on the BLTouch to make it 3.3V logic and used the Reprap configurator to generate all the necessary files. On startup, the BLTouch retracts and extends out its pin as it did with the MKSBase board I had before, the LED is off when pin is extended and red when pushed in by hand (after startup).

    However, it does not trigger when the pin hits the bed (checked with G30 S-1 and printer stops at z=0 with an error saying 'Z probe was not triggered during probing move. Stopped at height -0.000mm').

    Is my config.g wrong or is it my wiring (BLTouch was working when used MKSBase so do not think that is the issue).

    0_1540573531153_BL_touch wiring.jpg

    ; Configuration file for Duet WiFi (firmware version 1.21)
    ; executed by the firmware on start-up
    ; generated by RepRapFirmware Configuration Tool on Fri Oct 26 2018 15:17:24 GMT+0100 (British Summer Time)

    ; General preferences
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    ;*** The homed height is deliberately set too high in the following - you will adjust it during calibration.
    M665 R155 L397.19 B155 H520 ; Set delta radius, diagonal rod length, printable radius and homed height
    M666 X0 Y0 Z0 ; Put your endstop adjustments here, or let auto calibration find them

    ; Network
    M550 P########## ; Set machine name
    M551 P####### ; Set password
    M552 S1 ; Enable network
    M587 S"##########" P"######" ; Configure access point. You can delete this line once connected
    M586 P0 S1 ; Enable HTTP
    M586 P1 S1 ; Enable FTP
    M586 P2 S1 ; Enable Telnet

    ; Drives
    M569 P0 S0 ; Drive 0 goes backwards
    M569 P1 S0 ; Drive 1 goes backwards
    M569 P2 S0 ; Drive 2 goes backwards
    M569 P3 S1 ; Drive 3 goes forwards
    M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
    M92 X80 Y80 Z80 E798 ; Set steps per mm
    M566 X1200 Y1200 Z1200 E1200 ; Set maximum instantaneous speed changes (mm/min)
    M203 X18000 Y18000 Z18000 E1200 ; Set maximum speeds (mm/min)
    M201 X1000 Y1000 Z1000 E1000 ; Set accelerations (mm/s^2)
    M906 X1200 Y1200 Z1200 E1200 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 Z0 S1 ; Set minimum Z

    ; Endstops
    M574 X2 Y2 Z2 S1 ; Set active high endstops

    ; Z-Probe
    M307 H3 A-1 C-1 D-1 ; Disable heater on PWM channel for BLTouch
    M558 P9 H5 F120 T6000 ; Set Z probe type to bltouch and the dive height + speeds
    G31 P25 X0 Y20 Z0 ; Set Z probe trigger value, offset and trigger height
    M557 R150 S45 ; Define mesh grid

    ; Heaters
    M305 P0 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S280 ; Set temperature limit for heater 1 to 280C

    ; Fans
    M106 P0 S0.3 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P2 S1 I0 F500 H0 T50 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

    ; Tools
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
    G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

    ; Automatic power saving
    M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss

    ; Custom settings are not configured

  • Still have the same problem.

    I have checked the wiring and it is wired the same as the duet board of my friend that works. I have checked with his duet on my board and have the same problem. The resistance between the two pads on the bltouch is around 330 ohms after making sure the trace is cut.

    I have set the bed height to be z=0 using a piece of paper and jogging the print-head up and down. So the Z-probe trigger height should be correct no? How do I check/ set what the probe trigger height is?

    Is my Duet Wifi broken?

  • administrators

    Your wiring and config looks OK to me. Does the pin extend at the start of the probing move? Have you set up the deployprobe.g and retractprobe.g files, and tested them using M401 and M402?

  • @dc42

    Many thanks for the help. M401 and M402 didn't do anything - I checked those two files carefully against

    Issue was that in the deployprobe.g and retractprobe.g files, retract should have been M280 P3 S90 I1 (originally M280 P3 S90) and extend/ deploy should have been M280 P3 S10 I1 (originally M280 P3 S10). Once that was fixed, it worked!

    For those with the same issue, beware what RepRapFirmware Configuration Tool generates!

  • administrators

    Thanks for reporting the resolution. We'll update the configuration tool.


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