Delta calibration give wrong z height



  • Hello folks,

    Need advice.

    After doing the delta calibration I get less Z height than it actually is. Due to this problem, the first layer does not stick because it prints too high

    Real heigh for perfect first layer is: 514.250
    Calibration calculates that height is: ~513.680

    1. I calibrated the trigger heigh several times.
    2. The number of calibration factors or points does not give a different value
    3. I even made corrections for each point in bad.g
    4. I try to disable for G30
    ;G1 Z-5 F6000               ; move down a few mm so that the nozzle can be centred
    G90                        ; absolute positioning
    ;G1 X0 Y0 F6000             ; move X+Y to the centre
    

    No matter what I do, I always get a bad Z height: ~513.680.

    The current solution is to perform the calibration, save the parameters to the M500 and manually change H to 514.250. Then prints well and at a good height.
    But it doesn’t suit me, a solution is needed. Why auto calibration give wrong z height?

    Sensor Bl touch.

    config-override.g

    ; config-override.g file generated in response to M500 at 2020-06-23 11:10
    ; This is a system-generated file - do not edit
    ; Delta parameters
    M665 L404.947:404.947:404.947 R214.592 H513.698 B150.0 X0.012 Y0.108 Z0.000
    M666 X0.342 Y0.560 Z-0.902 A0.04 B-0.34
    ; Heater model parameters
    M307 H0 A90.0 C700.0 D10.0 S1.00 V0.0 B1
    M307 H1 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H2 A13.9 C21.5 D3.1 S1.00 V24.2 B0
    M307 H4 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H5 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H6 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    M307 H7 A340.0 C140.0 D5.5 S1.00 V0.0 B0
    ; Z probe parameters
    G31 T1 P500 X0.0 Y0.0 Z0.70
    G31 T3 P500 X0.0 Y0.0 Z0.70
    G31 T4 P500 X0.0 Y0.0 Z4.00
    G10 L2 P1 X0.00 Y0.00 Z0.00
    G10 L2 P2 X0.00 Y0.00 Z0.00
    G10 L2 P3 X0.00 Y0.00 Z0.00
    G10 L2 P4 X0.00 Y0.00 Z0.00
    G10 L2 P5 X0.00 Y0.00 Z0.00
    G10 L2 P6 X0.00 Y0.00 Z0.00
    G10 L2 P7 X0.00 Y0.00 Z0.00
    G10 L2 P8 X0.00 Y0.00 Z0.00
    G10 L2 P9 X0.00 Y0.00 Z0.00
    
    

    Bad.g (without H adjustments the result is the same)

    ; bed.g
    ; called to perform automatic delta calibration via G32
    ;
    ; generated by RepRapFirmware Configuration Tool v3.1.3 on Tue Jun 23 2020 11:05:25 GMT+0300 (Rytų Europos vasaros laikas)
    M561 ; clear any bed transform
    ; Probe the bed at 3 peripheral and 3 halfway points, and perform 4-factor auto compensation
    ; Before running this, you should have set up your Z-probe trigger height to suit your build, in the G31 command in config.g.
    G30 P0 X0 Y68.92 H0.014 Z-99999
    G30 P1 X69.28 Y-40 H-0.03 Z-99999
    G30 P2 X-69.28 Y-40 H-0.131 Z-99999
    G30 P3 X0 Y30.27 H-0.018 Z-99999
    G30 P4 X34.64 Y-20 H-0.04 Z-99999
    G30 P5 X-34.64 Y-20 H-0.036 Z-99999
    G30 P6 X0 Y0 H0 Z-99999 S4
    ; Use S-1 for measurements only, without calculations. Use S4 for endstop heights and Z-height only. Use S6 for full 6 factors
    ; If your Z probe has significantly different trigger heights depending on XY position, adjust the H parameters in the G30 commands accordingly. The value of each H parameter should be (trigger height at that XY position) - (trigger height at centre of bed)
    
    

    homedelta.g

    ; homedelta.g
    ; called to home all towers on a delta printer
    ;
    ; generated by RepRapFirmware Configuration Tool v2.1.8 on Wed Apr 01 2020 21:02:16 GMT+0300 (Rytų Europos vasaros laikas)
    G91                       ; relative positioning
    ;*** Slow homing has been configured. Change F6000 to F1800 below when your configuration is working
    G1 H1 X9999 Y9999 Z9999 F3000 ; move all towers to the high end stopping at the endstops (first pass)
    G1 H2 X-5 Y-5 Z-5 F1800   ; go down a few mm
    ;*** Slow homing has been configured. Change F180 to F600 below when your configuration is working
    G1 H1 X10 Y10 Z10 F180    ; move all towers up once more (second pass)
    ;G1 Z-5 F6000               ; move down a few mm so that the nozzle can be
    G90                       ; absolute positioning
    ;G1 X0 Y0 F3000            ; move X+Y to the centre
    
    

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