BLTouch strange x & y offset Duet Maestro, Reprap

Hi all

I just finished installing my new BLTouch to my Ender5 running on a Duet 2 Maestro.
Homing the bed with the BLTouch works fine, however when trying to execute the automatic mesh levelling, strange things are happening:

The head drives to x: 56.4 and y: 27.5 and starts levelling the bed from there on. Of course the head then drives over the length of the bed and would crash into the frame if not stopped in time.

I have set the probe to start from x: 10.0 and y: 10.0 but it always starts from the points stated above. Even reducing the mesh bed size to x: 10:100 and y: 10:100 does not help and the head would crash into the frame.

I really don't know where this misterious starting point comes from... I have set the probe offset to the nozzle correctly I guess and it's a completely different number than 56.4 / 27.5.

Here are the relevant parts of my config.g:

; Drives
M569 P0 S1                               ; physical drive 0 goes forwards
M569 P1 S0                               ; physical drive 1 goes backwards
M569 P2 S1                               ; physical drive 2 goes forwards
M569 P3 S0                               ; physical drive 3 goes backwards
M584 X0 Y1 Z2 E3                         ; set drive mapping
M350 X32 Y32 Z32 E64 I1                  ; configure microstepping with interpolation
M92 X160.00 Y160.00 Z800.00 E1617.05     ; set steps per mm
M566 X900.00 Y900.00 Z180.00 E120.00     ; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z1200.00 E1200.00 ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z100.00 E250.00     ; set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800 I30             ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                  ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                         ; set axis minima
M208 X230 Y225 Z300 S0                   ; set axis maxima

; Endstops
M574 X1 Y1 S1                            ; set active high endstops
M574 Z1 S2                               ; set endstops controlled by probe

; Z-Probe
M558 P9 H2 F120 T6000                    ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X-41.4 Y-12.5 Z2.68575          ; set Z probe trigger value, offset and trigger height
M557 X15:200 Y15:195 S20                 ; define mesh grid

bed.g:

M561 ; clear any bed transform
G28  ; home all axes
G29  ; probe the bed and enable compensation

homeall.g:

G91                     ; relative positioning
G1 H2 Z2 F6000          ; lift Z relative to current position
G1 H1 X-235 Y-230 F3000 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X5 Y5 F6000       ; go back a few mm
G1 H1 X-235 Y-230 F360  ; move slowly to X and Y axis endstops once more (second pass)
G90                     ; absolute positioning
G1 X10 Y10 F6000        ; go to first bed probe point and home Z
G30                     ; home Z by probing the bed

homez.g:

G91                  ; relative positioning
G1 H2 Z2 F6000       ; lift Z relative to current position
G90                  ; absolute positioning
G1 X10 Y10 F6000     ; go to first probe point
G30                  ; home Z by probing the bed

Does anybode have any suggestions?

Thanks a ton in advance!

The Z probe offsets declared in your G31 file are X-41.4 Y-12.5. The first probe point specified in your M557 command is X-15 Y-15. To put the probe over that point on the bed, the nozzle has to be moved to X=15-(-41.4)=56.8.

If you have set your M208 limits correctly, the firmware won't drive the head into the frame at the other end, it will leave out the points that are not reachable.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thank you very much for your reply, dc42!
I see that my M557 includes X15 Y15 not negative numbers?
Or did I get the point wrong on how to enter the BLTouch offset?
I have made a drawing on how I understood it (Attachment: Capture.PNG)

My bed measures 235x235 so M208 X230 Y225 Z300 S0 should be correct, even with some extra space?

What I have to say is that with the same M208 (of course other offset) auto bed levelling worked very well with your DC42 IR probe - but I had to change it because of my build surface which is partly white and that interferes a lot, so measures are not correct everywhere = bad adhesion)

If it helps, I also have an Ender-5 that I've put a Duet Maestro board on. I've not experienced what your talking about, so I've attached my configuration files if it helps. Looking at them, most of them are very close apart from your Endstops might be backwards unless you've physically relocated them. Most of my Ender-5 is stock apart from the Duet Maestro board and the BLTouch that I added.

config.g

; Configuration file for Duet Maestro (firmware version 1.21)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v2 on Sun Jun 23 2019 15:47:43 GMT-0400 (Eastern Daylight Time)

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

; Network
M550 P"Creality Ender 5"                           ; Set machine name
M552 Pxxx.xxx.xxx.xxx S1                             ; Enable network and set IP address
M553 Pxxx.xxx.xxx.xxx                                ; Set netmask
M554 Pxxx.xxx.xxx.xxx                                ; Set gateway
M586 P0 S1                                         ; Enable HTTP
M586 P1 S0                                         ; Disable FTP
M586 P2 S0                                         ; Disable Telnet

; Drives
M569 P0 S1                                         ; Physical drive 0 goes forward
M569 P1 S0                                         ; Physical drive 1 goes reverse
M569 P2 S1                                         ; Physical drive 2 goes forward
M569 P3 S1                                         ; Physical drive 3 goes forward
M350 X16 Y16 Z16 E16 I1                            ; Configure microstepping with interpolation
M92 X80.00 Y80.00 Z400.00 E93.00                   ; Set steps per mm
M566 X600.00 Y600.00 Z24.00 E300.00                ; Set maximum instantaneous speed changes (mm/min)
;M203 X18000.00 Y18000.00 Z300.00 E1500.00          ; Set maximum speeds (mm/min) (Original Marlin Values)
M203 X30000.00 Y30000.00 Z500.00 E6000.00          ; Set maximum speeds (mm/min) (Duet3d Forum Values for Ender-5)
;M201 X500.00 Y500.00 Z100.00 E5000.00              ; Set accelerations (mm/s^2) (Original Marlin Values)
M201 X500.00 Y500.00 Z200.00 E6000.00              ; Set accelerations (mm/s^2) (Duet3d Forum Values for Ender-5)
M906 X800.00 Y800.00 Z800.00 E800.00 I30           ; Set motor currents (mA) and motor idle factor in per cent
M84 S30                                            ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                                   ; Set axis minima
M208 X225 Y225 Z300 S0                             ; Set axis maxima

; Endstops
M574 X2 Y2 S1                                      ; Set active high endstops

; Z-Probe
M574 Z1 S2                                         ; Set endstops controlled by probe
M558 P9 H5 F120 T6000                              ; Set Z probe type to bltouch and the dive height + speeds
G31 P500 X-44 Y-16 Z2.325                          ; Set Z probe trigger value, offset and trigger height
M557 X5:225 Y10:225 S87:98                         ; Define mesh grid

; Manual Bed Leveling Assistant
M671 X66:225:225:66 Y44:44:214:214 P0.5

; Heaters (Autotune - M303 H0 S80 / M303 H1 S240)
M307 H0 A109.7 C358.3.3 D0.8 V23.9 S1.0 B0         ; Heater 0 model: gain 109.7, time constant 358.3, dead time 0.8, max PWM 1.00, calibration voltage 23.9
;M305 P0 T97700 B4619 C9.743561e-8 R2200           ; Alternative settings from Duet3d Forum
M305 P0 T98801 B4185 R2200                         ; Set thermistor + ADC parameters for heater 0
M143 H0 S80                                        ; Set temperature limit for heater 0 to 80C
M307 H1 A330.9 C115.6 D3.8 V24.0 S1.0 B0           ; Heater 1 model: gain 330.9, time constant 115.6, dead time 3.8, max PWM 1.00, calibration voltage 24.0
;M305 P1 T97700 B4619 C9.743561e-8 R2200           ; Alternative settings from Duet3d Forum
M305 P1 T98801 B4185 R2200                         ; Set thermistor + ADC parameters for heater 1
M143 H1 S280                                       ; Set temperature limit for heater 1 to 280C

; Fans
M106 P0 S0 I0 F500 H-1                             ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
M106 P1 S1 I0 F500 H1 T45                          ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P2 S1 I0 F500 H1:0 T45                        ; 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 S21 R23 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss

; Custom settings
M918 P1 E4                                         ; Enable 12864 LCD with 1 menu item per encoder click
M912 P0 S-7.25                                     ; Calibrate MCU temperature (Tr=24.35 - Tc=31.6)

; Pressure Advance
;M572 D0 S0.1

; Miscellaneous
T0                                                 ; Select first tool

bed.g

; bed.g
; called to perform automatic bed compensation via G32
;
; generated by RepRapFirmware Configuration Tool v2 on Sun Jun 23 2019 15:47:42 GMT-0400 (Eastern Daylight Time)
;M561 ; clear any bed transform
;G29  ; probe the bed and enable compensation
M290 R0 S0	; clear any existing baby-stepping
M561		; clear any bed transform
; ManualBed Adjustment Assistant
G30 P0 X22 Y28 Z-99999 		; probe near an adjusting screw
G30 P1 X181 Y28 Z-99999 	; probe near an adjusting screw
G30 P2 X181 Y198 Z-99999 	; probe near an adjusting screw
G30 P3 X22 Y198 Z-99999 S4	; probe near an adjusting screw and report adjustments needed
G1 X112.5 Y112.5 F9000

homeall.g

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v2 on Sun Jun 23 2019 15:47:43 GMT-0400 (Eastern Daylight Time)
G91                   ; relative positioning
G1 Z5 F6000 S2        ; lift Z relative to current position
G1 S1 X250 Y230 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 X-5 Y-5 F6000      ; go back a few mm
G1 S1 X250 Y230 F360  ; move slowly to X and Y axis endstops once more (second pass)
G90                   ; absolute positioning
G1 X156.5 Y128.5 F6000      ; go to first bed probe point and home Z
G30                   ; home Z by probing the bed

; Uncomment the following lines to lift Z after probing
G91                  ; relative positioning
G1 S2 Z5 F100        ; lift Z relative to current position
G90                  ; absolute positioning

home.g

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v2 on Sun Jun 23 2019 15:47:43 GMT-0400 (Eastern Daylight Time)
G91              ; relative positioning
G1 Z5 F6000 S2   ; lift Z relative to current position
G90              ; absolute positioning
G1 X156.5 Y128.5 F6000 ; go to first probe point
G30              ; home Z by probing the bed

; Uncomment the following lines to lift Z after probing
G91             ; relative positioning
G1 S2 Z5 F100   ; lift Z relative to current position
G90             ; absolute positioning

And I've also attached a picture of what my Ender-5 head looks like with relation to where the BLTouch is mounted.


I've not had any issues with the Duet Maestro board on the Ender-5 so much so that I have a Titan Aero to install on it and I'm hesitant to install it because its printing beautifully at the moment without any issues just using the stock hotend with the addition of the BLTouch.