BLTouch getting triggered



  • I am using BLTouch, and it seems i cannot make a full Mesh, i tried lowering the speed and error stays the same.
    Also tried varying the probe trigger value and its still the same.
    i also shut off the hotend fan and other stuff that might cause unusual vibration triggering the probe, and its the same.

    [[language]]
    Firmware Name:	RepRapFirmware for Duet WiFi
    Firmware Electronics:	Duet WiFi 1.0
    Firmware Version:	1.20.1RC2 (2018-01-01)
    WiFi Server Version:	1.20
    Web Interface Version:	1.20
    
    
    [[language]]
    ; Endstops
    M574 Z0 S0 ; Set active low endstops
    M574 X1 Y1 S1 ; Set active high endstops
    M558 P5 X0 Y0 Z0 H7 F80 T1600; Set Z probe type to unmodulated, the axes for which it is used and the dive height + speeds  BLTOUCH
    G31 P150 X15 Y0 Z3.657; Set Z probe trigger value, offset and trigger height BLTOUCH
    M557 X5:270 Y0:270 S40.8 ; Define mesh grid
    
    
    [[language]]
    7:29:28 PMError: Z probe already triggered before probing move started
    7:28:42 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    7:28:13 PMError: Z probe already triggered before probing move started
    7:28:04 PMWarning: Skipping grid point (5.0, 40.8) because Z probe cannot reach it
    Warning: Skipping grid point (5.0, 81.6) because Z probe cannot reach it
    7:26:39 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    7:26:27 PMError: Z probe already triggered before probing move started
    7:26:20 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    7:25:59 PMConnection established!
    7:25:31 PMDisconnected.
    7:24:04 PMError: Z probe already triggered before probing move started
    7:24:00 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    7:23:22 PMError: Z probe already triggered before probing move started
    7:23:12 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    7:22:45 PMError: Z probe already triggered before probing move started
    7:22:19 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    7:22:10 PMError: Z probe already triggered before probing move started
    7:21:28 PMG29
    Warning: Skipping grid point (5.0, 0.0) because Z probe cannot reach it
    
    

  • administrators

    You may need to increase the dive height (H) or travel speed (T) in the M558 command to ensure that the probe is clear of the bed when it extends again. Also your M557 parameters are asking it to probe at points that cannot be reached - probably the probe can't reach X=0 because it has an X offset.



  • also i notice when i run the mesh compensation after homing, the probe drops first before the lift, making it hit the bed for a split second ( you can hear the click of the probe tip to the bed)



  • Do you use a macro to start mesh compensation? If so, I'd suggest calling G28 (to home), followed by:

    [[language]]
    ; assumes there are gcodes before this point to home the machine
    G91 ; set relative movements
    M400 ; ensure the homing movements are complete
    G1 Z5 ; get the nozzle away from the bed
    G4 S1 ; wait for the movement to actually finish - might have to increase S1 to S2
    M401 ; deploy the probe
    G29 ; start mesh checks
    M402 ; make sure the probe is retracted
    
    

    Any other place that you use the BLTouch, such as G30 calls, see what happens if you don't call "M401" and see if it works. I've found that many times I had explicit calls to M401 they weren't needed because the duet firmware knew to deploy on it's own. (It's a bit of trial and error to get it right.)

    Also, any time you do use the probe, ensure that you explicitly move the nozzle away from the bed (or the bed away from the nozzle) before any probe related gcodes.



  • yes i home all then run mesh compensation button.
    compensation does not complete fully and if it does i see all red on the viewer and it is way above.
    i will try to make a macro over your script.

    Machine:
    hypercube evolution.



  • M574 Z0 S0?

    What's in your homeall.g and homez.g scripts?

    A question I don't know the answer to (and probably not related to the original post): If using a BLTouch to home Z, shouldn't the M574 line for Z be "M574 Z1 S2"?

    Edit: added that my question probably isn't directly related to the OP's question


  • administrators

    @pao_wikhan:

    yes i home all then run mesh compensation button.
    compensation does not complete fully and if it does i see all red on the viewer and it is way above.
    i will try to make a macro over your script.

    Machine:
    hypercube evolution.

    Did you see my reply yesterday?



  • Hi David, Gary, yes. i am tweaking the probe speed, dive height and travel speed, also probe trigger value;; looking for that good value.
    as for homing concerns it is homing indeed. but when i do a mesh compensation, it then reaches a point where the calibration stops or ends up with the 1000 value.
    im not sure if external factors are triggering the probe to be that.

    should i set M574 Z0 Snnn, n being 2? also Z1 or Z0?



  • Depending on the contents of your homeall and homez files, the parameters for M574 I mentioned might not matter. (If you home Z using G30, they don't matter.)

    As for your problem, I'd like to try and help, but I'm not sure I'm understanding the problem. There aren't enough details for me to completely understand. Is the BLTouch going into an error (flashing red) state when the mesh probing stops working properly?

    If you're BLTouch probe is triggering when your nozzle is still over 3mm from the bed (as indicated by your G31 command), then you're probably going to need a larger "dive height" on the M558 command. Try going to 10. (That's the H parameter on the M558 command.)

    Try this: comment out your existing M558 command (don't delete it - just put a semi-colon in front of it) and add this one :
    M558 P5 X0 Y0 Z1 H10 F100 T4000

    (This is what I'm using and it works great. The only difference is that I have a H of 5, but my trigger height is less than 1mm.)

    After you save the config.g and the duet restarts, go into the web page, to the G-Code Console page, and type "M558" (With no parameters) and hit 'Send'. It should respond by showing you something similar to:

    "Z Probe type 5, invert no, dive height 10.0mm, probe speed 100mm/min, travel speed 4000mm/min, recovery time 0.00 sec, max taps 1, max diff 0.01"

    (This is just to ensure that the M558 command worked properly.)

    Please post back letting us know how this works out.

    Take care
    Gary



  • im guessing its a hardware thing. so i've removed the bed and trying to make it all be straight and aligned again.
    will inform you when im back to software troubleshooting again.



  • okay so now im having this.

    [[language]]
    G29
    Error: Z probe already triggered before probing move started
    
    


  • this is what i get when i center and do a home now.

    [[language]]
    
    2:50:26 PMG30 S-1
    Stopped at height 3.962 mm  Z=3.96
    2:49:13 PMG1 Z10 F200
    2:49:05 PMG30 S-1
    Stopped at height 3.968 mm    Z=3.97
    2:48:57 PMG1 Z10 F200
    2:48:51 PMG92 Z0
    
    

    it seems the height is varying



  • [[language]]
    2:59:53 PMG30 S-1
    Stopped at height 4.013 mm                    Z=4.01
    2:59:41 PMG1 Z10 F200
    2:59:15 PMG30 S-1
    Stopped at height 3.995 mm                     Z=4.00
    2:59:03 PMG1 Z10 F200
    2:58:01 PMG30 S-1
    Stopped at height 3.968 mm                     Z=3.97
    2:57:48 PMG1 Z10 F200
    2:56:52 PMG1 Z0
    2:56:38 PMG30 S-1
    Stopped at height 3.978 mm                      Z=3.98
    2:56:25 PMG1 Z10 F200
    2:56:17 PMG92 Z0
    2:55:36 PMG92 Z10
    2:55:27 PMG31 P100 X0 Y0 Z3.97;
    2:55:15 PMM558 P5 X0 Y0 Z1 H10 F100 T4000
    2:54:51 PMG1 Z0
    2:54:42 PMG28 Z
    2:54:31 PMG1 X145 Y135 F2200
    2:53:58 PMConnection established!
    
    

    i settled with 3.97 as Zoffset

    [[language]]
    G29
    9 points probed, mean error 8.429, deviation 0.212
    Height map saved to file heightmap.csv
    
    

    looking at the height map.its like its in the air.

    [[language]]
    RepRapFirmware height map file v2 generated at 2018-01-02 15:02, mean error 8.429, deviation 0.212
    xmin,xmax,ymin,ymax,radius,xspacing,yspacing,xnum,ynum
    10.00,290.00,0.00,270.00,-1.00,108.80,108.80,3,3
      8.383,  8.271,  8.016
      8.469,  8.403,  8.299
      8.609,  8.731,  8.682
    
    


  • now when i center again and run a G28 Z the Z is showing -12.84

    im lost now..as when i run all the necessary parameters to ensure the bed to nozzle height changes.



  • reran G29 and now this is the height map.

    [[language]]
    RepRapFirmware height map file v2 generated at 2018-01-02 15:37, mean error 8.530, deviation 0.221
    xmin,xmax,ymin,ymax,radius,xspacing,yspacing,xnum,ynum
    10.00,290.00,0.00,270.00,-1.00,108.80,108.80,3,3
      8.489,  8.348,  8.118
      8.582,  8.517,  8.362
      8.716,  8.834,  8.805
    
    

    when i do a G28 Z and Z0, the offset is correct. is it possible that compensation is not working?



  • this is the updated endstop on config.g

    [[language]]
    ; Endstops
    M574 Z0 S2 ; Set active low endstops
    M574 X1 Y1 S1 ; Set active high endstops
    M558 P5 X0 Y0 Z1 H10 F100 T4000
    G31 P100 X0 Y0 Z4.7
    M557 X10:290 Y0:270 S108.8 ; Define mesh grid
    
    

  • administrators

    How are you homing Z?

    After homing Z, does Z=0 correspond to the position when the nozzle is just touching the bed?



  • yes. i think i got it now.
    weird part is there is a deviation value that is ~8mm
    and it is always there.

    [[language]]
    Number of probe points: 9
    
    Probe area: 473.5 cm²
    
    Maximum deviations: 7.699 / 8.365 mm
    
    Mean error: 8.077 mm
    
    RMS error: 0.198 mm
    
    

  • administrators

    That mean error suggests to me that you have an 8mm error in your Z=0 position after homing and before bed probing.



  • Thanks All!
    David, Gary, and the guys on the hevo FB group that are here.
    im doing a test print, and ti seems like the offset changes.
    i had to do a babystep to compensate the offset.

    BTW, i updated my firmware to RC1 and it appears to be better.

    [[language]]
    Firmware Electronics:	Duet WiFi 1.02 or later
    Firmware Version:	1.21RC1 (2018-01-25)
    WiFi Server Version:	1.20
    Web Interface Version:	1.20
    
    

    Someone asked me to upload my home files.

    homeall

    [[language]]
    ; homeall.g
    ; called to home all axes
    ;
    ; generated by RepRapFirmware Configuration Tool on Wed Dec 27 2017 18:31:34 GMT+0800 (PHT)
    G91                     ; relative positioning
    G1 Z7 F800           ; lift Z relative to current position
    M280 P3 S160 I1    ;Clear any alarm
    ;M401			; deploy probe
    G1 S1 X-305 Y-305 F1800 ; move quickly to X or Y endstop and stop there (first pass)
    G1 S1 X-305             ; home X axis
    G1 S1 Y-305             ; home Y axis
    G1 X5 Y5 F360000        ; go back a few mm
    G1 S1 X-305 F360        ; move slowly to X axis endstop once more (second pass)
    G1 S1 Y-305             ; then move slowly to Y axis endstop
    G90                     ; absolute positioning
    G1 X10 Y0 F360000        ; go to first bed probe point and home Z
    G30                     ; home Z by probing the bed
    ;G1 Z0 F100;            ; uncomment this line to lift the nozzle after homing
    
    

    homeZ

    [[language]]
    ; homez.g
    ; called to home the Z axis
    ;
    ; generated by RepRapFirmware Configuration Tool on Wed Dec 27 2017 18:31:34 GMT+0800 (PHT)
    ;M280 P7 S160 I1    ;Clear any alarm
    G91              ; relative positioning
    G1 Z7 F800           ; lift Z relative to current position
    G90              ; absolute positioning
    ;G1 X10 Y0 F6000 ; go to first probe point
    G30              ; home Z by probing the bed
    
    

 

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