@b3njam1n Hey! just use the code snipet and paste your gcode inside it.

I am glad to report that now it's working. But just because i am a control freak i 've modified my bed so its better now and i am assuming that once i've done the compensation and save the height map the only thing that i need to do is just load that map at the beginning of the print.

Thanks guys

@Phaedrux no, it's behind the nozzle, maybe i wrongly put positive 6 when it is negative? That's why i am sure that every single coordinate can be reach i've saw myself the whole measurement and the probe can reach all of them fine.

@Veti

Config.g

; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.2.1 on Tue Jan 12 2021 22:19:26 GMT-0500 (EST)

; General preferences
G90                                           ; send absolute coordinates...
M83                                           ; ...but relative extruder moves
M550 P"Ender 3 Pro"                           ; set printer name

; Network
M552 S1                                       ; enable network
M586 P0 S1                                    ; enable HTTP
M586 P1 S0                                    ; disable FTP
M586 P2 S1                                   ; disable Telnet

; Drives
M569 P0 S0                                    ; physical drive 0 goes backwards
M569 P1 S0                                    ; physical drive 1 goes backwards
M569 P2 S1                                    ; physical drive 2 goes forwards
M569 P3 S0                                    ; physical drive 3 goes forwards
M584 X0 Y1 Z2 E3                              ; set drive mapping
M350 X16 Y16 Z16 E16 I1                        ; configure microstepping without interpolation
;M350 E16 I1                                   ; configure microstepping with interpolation

M92 X80.00 Y80.00 Z397.44 E449.62              ; set steps per mm
M566 X900.00 Y900.00 Z24.00 E180.00           ; set maximum instantaneous speed changes (mm/min)
M203 X7000.00 Y7000.00 Z5000.00 E500.00      ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z150.00 E350.00         ; set accelerations (mm/s^2)
M906 X900 Y900 Z900 E900 I60                  ; set motor currents (mA) and motor idle factor in per cent
M84 S40                                       ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                              ; set axis minima
M208 X230 Y210 Z200 S0                        ; set axis maxima

; Endstops
M574 X1 S1 P"xstop"                           ; configure active-high endstop for low end on X via pin xstop
M574 Y1 S1 P"ystop"                           ; configure active-high endstop for low end on Y via pin ystop
M950 H3 C"nil"                                 ; Disable heaters h3-h7 to free up pins
M574 Z1 S2                                    ; configure Z-probe endstop for low end on Z


; Z-Probe

M950 S0 C"exp.heater3"; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H6 F200 T2000           ; set Z probe type to bltouch and the dive height + speeds

M280 P0 S10 ; send control signal to BLTouch through servo/gpio 0

;Bed Height adjustments

G31 P500 X-46 Y6 Z3.34   ; set Z probe trigger value, offset and trigger height
M557 X47:205 Y20:230 S20                      ; define mesh grid
;M557 X47:205 Y20:230 S32                      ; define mesh grid

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T98801 B4185 ; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bedheat" T0                         ; create bed heater output on bedheat and map it to sensor 0
;M307 H0 B0 S1.00                              ; disable bang-bang mode for the bed heater and set PWM limit
M307 H0 R0.304 C437.7 D7.20 S1.00 V24.0


M140 H0                                       ; map heated bed to heater 0
M143 H0 S80                                   ; set temperature limit for heater 0 to 80C
M308 S1 P"e0temp" Y"thermistor" T98801 B4185  ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1                          ; create nozzle heater output on e0heat and map it to sensor 1
;M307 H1 B0 S1.00                              ; disable bang-bang mode for heater  and set PWM limit
;M307 H1 R2.305 C156.6 D6.40 S1.00 V24.0
M307 H1 R2.303 C154.7 D6.52 S1.00 V24.0
M143 H1 S250                                  ; set temperature limit for heater 1 to 250C



; Fans
M950 F0 C"fan0" Q500                          ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H T45                              ; set fan 0 value. Thermostatic control is turned on
M950 F1 C"fan1" Q500                          ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T45                             ; set fan 1 value. Thermostatic control is turned on

; Tools
M563 P0 S"Hotend" D0 H1 F0                    ; 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

; Custom settings are not defined

; Miscellaneous
T0                                            ; select first tool
G28


;M558 P9 H5 F100 T2000
;M558 P9 C"^zprobe.in" H5 F100 T2000  ; BLTouch connected to Z probe IN pin
;M950 S0 C"exp.heater3" ; create servo/gpio 0 on heater 3 pin on expansion connector
...

;G31 X-46 Y6 Z3.02 
;M501

M208

1/31/2021, 11:22:02 AM	M208
Axis limits X0.0:230.0, Y0.0:210.0, Z0.0:200.0

G31

1/31/2021, 11:23:07 AM	G31
Z probe 0: current reading 0, threshold 500, trigger height 3.340, offsets X-46.0 Y6.0

@Veti But when i defined the grid i used the probe as point of reference thats why in reality all that coordinates are indeed reachable.

Well trying again to set the bltouch right. I did some modification to the bed, i 've replaced the springs for m3 spacers so the bed is really steady also there where a severe difference between the spacers been used in the bed gantry i don't know how did that machine pass the "quality test" but now the bed has little margin of error

BUT yep there is always that frightening word, the freaking compensation is not working when i run the bed compensation i get this on some mesh parts:

1/31/2021, 10:11:05 AM	Warning: Skipping grid point (47.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (67.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (87.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (107.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (127.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (147.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (167.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (187.0, 220.0) because Z probe cannot reach it
70 points probed, min error -0.034, max error 0.477, mean 0.251, deviation 0.152
Height map saved to file 0:/sys/heightmap.csv
1/31/2021, 10:11:04 AM	Warning: Skipping grid point (47.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (67.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (87.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (107.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (127.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (147.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (167.0, 220.0) because Z probe cannot reach it
Warning: Skipping grid point (187.0, 220.0) because Z probe cannot reach it
70 points probed, min error -0.034, max error 0.477, mean 0.251, deviation 0.152
Height map saved to file 0:/sys/heightmap.csv
1/31/2021, 10:10:45 AM	Warning: Skipping grid point (187.0, 180.0) because Z probe cannot reach it
Warning: Skipping grid point (187.0, 200.0) because Z probe cannot reach it
1/31/2021, 10:10:05 AM	Warning: Skipping grid point (187.0, 140.0) because Z probe cannot reach it
Warning: Skipping grid point (187.0, 160.0) because Z probe cannot reach it
1/31/2021, 10:09:26 AM	Warning: Skipping grid point (187.0, 100.0) because Z probe cannot reach it
Warning: Skipping grid point (187.0, 120.0) because Z probe cannot reach it

The thing is that all of that coordinates can indeed be reached by the prove i've seen all the measurement itself and i can tell you that non of that coordinates are unreachable. So there might be something else wrong.

this is my actual G31 part:

G31 P500 X-46 Y6 Z3.34   ; set Z probe trigger value, offset and trigger height

If a run a test print the print is ok but i don't want to try a really big print if i am not sure that the bltouch is working the way it should.

Any ideas?

@Phaedrux I 've been asking the same question for a couple of days now, today i will get a caliper and i will be able to measure it correctly.

Sometimes it's the little things that get overlooked

Amen to that!!!!

I'll make a video of it.

I 've had it with this, it keeps happening the same all over again. I guess there is something wrong with the bltouch. I have done a manual level of the freaking bed that i thing it would be perfect. Then i follow the guide again and the result is that the homing of the z axis is in the middle of the bed but the damn nozzle is really way too up to even try an auto level .