Bl Touch strange behavior

  • Hello there!
    It was working...until it was not...

    The new behavior is, when I follow the tutorials on how to define the trigger height (using G30 S-1) it works on the 1st try then on the second the pin drops again after returning the value and Bl touch enters in error mode.

    When I try to make a mesh compensation which it was doing before, now it stops in some point returning an error that probe was not triggered.

    sometimes even the Z homing fails

    the autobed compensation seems to work, although the visual results for me seems a little extreme

    The only thins I did between the working and non working moments:

    I fixed the Z steps /mm Z was half the way it should be

    And I raized a bit the Bltouch to respect the 8mm from the nozzle tip.


  • Moderator

    Can you post your config.g?

    When you changed the steps per mm did you adjust the offset and dive height? Sounds like something is just a little off now.

  • I did, but maybe I did wrong...

    It had a dive of 5 but was diving 2.5 because if the error in the steps... When reading about in some forum people was telling to raise the dive value so I raised to 10 thento 20... No effect... I will try 2.5 now

    The trigger height is bugging me, because I see the value to high its around 5.585..sometimes it goes down to 3.377....i don't know why this strong variation occurs between readings...

  • Hi there, good morning!

    Here is what happens when I try mesh compensation. I tried to lower the dive to 2.5 and 2 mm but had no effect at all.. actyally seemed to be worst

    probe video


  • Please check all the behaviors in video...

    Bed compensation video

    homing video


    ; Configuration file for Duet WiFi (firmware version 1.20 or newer)
    ; executed by the firmware on start-up
    ; generated by RepRapFirmware Configuration Tool on Mon May 07 2018 16:11:49 GMT+0200 (Hora de verano romance)

    ; General preferences
    M584 X0 U1 Y2 Z11 E3:4 ; Create U axis for second X carriage before we try to configure it (EDITADO POR 3DEALO - U DRIVE)
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    ; Network
    M550 PDuettest ; Set machine name
    M552 S1 ; Enable network
    M587 S"" P"*" ; Configure access point. You can delete this line once connected
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Drives
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S0 ; Drive 1 goes BACKWARDS
    M569 P2 S0 ; Drive 2 goes BACKWARDS
    M569 P3 S0 ; Drive 3 goes BACKWARDS
    M569 P4 S1 ; Drive 4 goes forwards (EDITADO POR 3DEALO - U DRIVE)
    M569 P11 S0 ; Drive 11 goes forwards (EDITADO POR 3DEALO - U DRIVE)
    M350 X32 Y32 U32 Z16 E32:32 I0 ; Configure microstepping without interpolation (EDITADO POR 3DEALO - Z DRIVE COM 16 PASSOS)
    M92 X160 Y160 U160 Z1600 E1668 ; Set steps per mm (EDITADO POR 3DEALO - U DRIVE)
    M566 X900 Y900 U900 Z50 E120 ; Set maximum instantaneous speed changes (mm/min) (EDITADO POR 3DEALO - U DRIVE)
    M584 X0 U1 Y2 Z11 E3:4 ; SECOND TIME Create U axis for second X carriage before we try to configure it (EDITADO POR 3DEALO - U DRIVE)
    M203 X6000 Y6000 U6000 Z1000 E1200 ; Set maximum speeds (mm/min) (EDITADO POR 3DEALO - U DRIVE)
    M201 X1000 Y500 U1000 Z200 E250 ; Set accelerations (mm/s^2) (EDITADO POR 3DEALO - U DRIVE)
    M906 X800 Y1200 U800 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent (EDITADO POR 3DEALO - U DRIVE SETAGEM MANUTAL NO PROPRIO DRIVE DRV)
    G21 ; Work in millimetres (EDITADO POR 3DEALO - U DRIVE)
    G90 ; Send absolute coordinates... (EDITADO POR 3DEALO - U DRIVE)
    M83 ; ...but relative extruder moves (EDITADO POR 3DEALO - U DRIVE)
    M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 X-76 Y0 U0 Z-10 S1 ; Set axis minima (EDITADO POR 3DEALO - U DRIVE)

    ; Endstops
    M574 X0 Y0 U2 S0 ; Set active LOW endstops (EDITADO POR 3DEALO - U DRIVE com endstop high end)
    M574 Z1 S2 ; Set endstops controlled by probe

    M591 D0 P1 C2 ;Filament sensor for E0, plugged into Z endstop (C2), set as a simple switch (P1)
    M591 D1 P1 C4 ;Filament sensor for E1, plugged into E1 endstop (C4), set as a simple switch (P1)

    ; Z-Probe (BL Touch)
    M307 H7 A-1 C-1 D-1
    M558 P9 H2 F1000 T4000 X0 Y0 Z1 ; Set Z probe type/mode 9. H=Dive Height. F=Speed the Z moves
    G31 P25 X-34 Y18 Z3.377 ; Set Z probe trigger value, offset and trigger height
    M557 X20:580 Y20:420 S40 ; Define mesh grid

    ; Heaters
    M301 H0 S1.00 P10 I0.1 D200 T0.4 W180 B30 ; Use PID on bed heater (may require further tuning)
    M305 P0 T100000 B3950 C0 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S100 ; Set temperature limit for heater 0 to 100C
    M305 P1 T100000 B3950 C0 R4700 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S270 ; Set temperature limit for heater 1 to 270C
    M305 P2 T100000 B3950 C0 R4700 ; Set thermistor + ADC parameters for heater 2
    M143 H2 S270 ; Set temperature limit for heater 2 to 270C

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

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

    ;''' Tool configuration section'''

    ;''' Create a tool that uses the low end (X) carriage'''

    M563 P0 D0 H1 F0 ; tool 0 uses extruder 0, heater 1 and fan 0
    G10 P0 X0 Y0 Z0 S0 R0 ; set tool 0 offsets and temperatures

    ;''' Create a tool that uses the high end (U) carriage'''

    M563 P1 D1 H2 X3 F2 ; tool 1 uses extruder 1, heater 2, fan 2, and maps X to U
    G10 P1 Y0 U0 Z0 S0 R0 ; set tool 1 offsets and temperatures

    ;''' Create a tool that prints 2 copies of the object using both carriages'''

    M563 P2 D0:1 H1:2 X0:3 F0:2 ; tool 2 uses both extruders, hot end heaters and fans, and maps X to both X and U
    G10 P2 X50 Y0 U-50 S0 R0 ; set tool offsets and temperatures
    M567 P2 E1:1 ; set mix ratio 100% on both extruders

    ; 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

  • Ok, I just discovered something very important

    No matter what configuration I put on the Z steps / mm it will behave the same way.... its aways wrong by a half. When I tell to raise 100mm it will raise only 5mm

    I'm using my Z on a external driver:

    alt text

  • administrators

    1. Please move your M584 command to the line immediately after the M569 lines. As stated in the wiki, M584 must be before other commands that relate to axes, such as M350, M906 etc.

    2. What type of external driver are you using? The Duet is a fast board and the step pulses generated by default are too fast for many types of external driver. You may need to use a T parameter in the M569 P11 command to slow down the step pulse timing for your driver.

    3. The default Z probe dive height is 5mm. The only benefit to using lower values is to speed up probing (so that the Z probe has less distance to go before it touches the bed), and that will only work if the bed is flat and the machine is well-calibrated. So don't use a height less than 5mm unless those conditions are met. Using a higher dive height such as 10mm may be helpful if you are not sure of the trigger height of your Z probe.

    4. You have a high probing speed (F1000) in your M558 command, but the wiki page about connecting a bltouch recommends F100. So i suggest you change to F100, at least until everything is working.

    HTH David

  • Thanks David,
    I just received a TB6600 I will replace the other one with it. I was using this little red board wich accepts botth drvs and a4988...

    any tips in tb6600 ?

  • administrators

    The TB6600 datasheet doesn't publish the full set of step pulse timing parameters, however I think using T2.2 or a little higher in the M569 command for that driver should work.

    AFAIR, A4988 drivers need T1 and DRV8825 need T2.5.

  • @dc42 Can I hook the TB6600 to the same DRIVER 11 I was hooking the nameless little red board?

    Also I am configuring its jumpers to:

    32 microsteps / 64000 pulse/rev
    Current 1.5 peak 1.7

    Is that ok for a NEMA 17 setup and the Duet wifi?

    I have a breakout expansion from duet, but I'd not like to use, if its posible. Looking to the connectinos I have available on the conn_lcd, I miss all the GROUNDs for Enable, Dir an Pul

  • The dive height is too low, the probe pin is bouncing of your bed. I guess at one point of the bed the probe is even not able to fully deploy, triggering the error state. I started with 8mm just to be safe, I also added a delay to the M558 command. I set R to 1, to give the probe one second to deploy.

    After I got that working I decreased R to 0.3 which is still a bit much, but it makes sure that the probe has enough time to deploy. I can probably decrease the height as well. But failures in probing can quickly result in the nozzle crashing into the bed so I rather stay on the safe side. But I have to admit that probing many points with high values take considerably more time.

    Edit: Oh, one more thing. The probe should completely deploy, and then it should move down until it triggers which then retracts it again. In your video it looks like that's all happening at once which the BLTouch doesn't like in my opinion.

  • Everything is working. Thanks you all! I will post all the right settings for future use.

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