Problem with setting my z-offset

Torin

Hi,
I have recently started to re-animate my old printer and I have some troubles with setting properly offset for my BLTouch. So doesnt' really matter what I am going to put in the setting it's still probing it in the same place.

My config.g

; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Oct 15 2020 18:56:39 GMT+0100 (British Summer Time)

; General preferences
G90                                            ; send absolute coordinates...
M83                                            ; ...but relative extruder moves
M550 P"Ender 3 Pro"                            ; set printer name
M918 P1 E4 F2000000                            ; configure direct-connect display

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

; Drives
M569 P0 S1                                     ; physical drive 0 goes forwards
M569 P1 S1                                     ; physical drive 1 goes forwards
M569 P2 S0                                     ; physical drive 2 goes backwards
M569 P3 S1                                     ; physical drive 3 goes forwards
M584 X0 Y1 Z2 E3                               ; set drive mapping
M350 E128 I0                                   ; configure microstepping without interpolation
M350 X16 Y16 Z16 I1                            ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z400.00 E1095.00             ; set steps per mm
M566 X1200.00 Y1200.00 Z24.00 E300.00          ; set maximum instantaneous speed changes (mm/min)
M203 X9000.00 Y9000.00 Z180.00 E6000.00        ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z100.00 E5000.00          ; set accelerations (mm/s^2)
M906 X800 Y800 Z800 E1000 I50                  ; 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 X235 Y235 Z260 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
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" H5 F120 T6000            ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X-43 Y-80 Z2.5                        ; set Z probe trigger value, offset and trigger height
M557 X15:215 Y15:195 S20                       ; define mesh grid

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B4092 ; 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
M140 H0                                        ; map heated bed to heater 0
M143 H0 S110                                   ; set temperature limit for heater 0 to 110C
M308 S1 P"e0temp" Y"thermistor" T100000 B4092  ; 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

; Fans
M950 F0 C"fan0" Q500                           ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1                                 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan1" Q500                           ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T35                              ; set fan 1 value. Thermostatic control is turned on
M950 F2 C"fan2" Q500                           ; create fan 2 on pin fan2 and set its frequency
M106 P2 S1 H1:0 T45                            ; set fan 2 value. Thermostatic control is turned on

; Tools
M563 P0 S"MicroSwiss" 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
M575 P1 S1 B57600                              ; enable support for PanelDue
M501                                           ; load saved parameters from non-volatile memory
T0                                             ; select first tool

and config-override.g

; config-override.g file generated in response to M500 at 2020-10-15 18:38
; This is a system-generated file - do not edit
; Heater model parameters
M307 H0 A61.5 C233.7 D1.5 S1.00 V23.9 B0
M307 H1 A375.7 C136.8 D4.6 S1.00 V24.1 B0
; Workplace coordinates
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

; Filament sensor
M591 P1 C"e0_stop" S1 D0

I believe offset should be properly set via G31 P500 X-43 Y-80 Z2.5 but somehow whenever I change to anything probe probes in the same place. My probe is in front left of the printer.
Did I do some stupid mistake anywhere?

fcwilt

@Torin

Hi,

The X and Y parameters of G31 specify the location of the probe relative to the nozzle tip.

Are those values correct?

To position the probe on X and Y you use a normal G1 movement command taking into account the probe offsets in G31.

Let's call Xd and Yd the co-ordinates of the desired location to probe.

Let's call Xo and Yo the offsets specified in G31.

The command to position the probe would G1 X(Xd-Xo) Y(Yd-Yo).

Now you cannot do the math in the G1 command like I have shown, you simply first determine what those values would be and use them directly.

For example, let's assume a bed of 300 x 300 and you wish to probe at 150,150.

Let's also assume probe offsets of X10 and Y20.

The command would be G1 X140 Y130

You also have to be sure that you can move the probe to the desired point(s) without other parts of the extruder assembly hitting something.

Frederick

Torin

That makes sense, but what I should do if I want to home Z and the probe goes slightly outside bed and doesn't hit anything? I would assume z probe offset is for that and firmware should compsensate that?
No matter what I will set in

G31 P500 X43 Y13 Z2.5                        ; set Z probe trigger value, offset and trigger height
M557 X80:140 Y80:140 S20                       ; define mesh grid

it still wants to probe in the same place outside bed.

Veti

@Torin said in Problem with setting my z-offset:

home Z and the probe goes slightly outside bed and doesn't hit anything? I

see homez.g for the location for homing

Torin

Good shout, but unfortunately not enough

home-z.g contents

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Oct 15 2020 18:56:39 GMT+0100 (British Summer Time)
G91              ; relative positioning
G1 H2 Z5 F6000   ; lift Z relative to current position
G90              ; absolute positioning
G1 X58 Y48 F6000 ; go to first probe point
G30              ; home Z by probing the bed

After changing and restarting it still probes the old place, despite me adjusting it in G1 over there. When I invoke G1 X58 Y48 it goes to the good point though where the probe wouldn't hit air...

Veti

are you executing home z or homeall?

check your homeall as well in case you are homing all axis

Torin

Yeah I was doing home-all. Cheers dude. That did the trick.
Happy Friday.

Sid stupid question, any chance I can put those in reprap configuration tool somehow just in case I will forget about those changes and have them in JSON file?

Veti

@Torin
if you had put the offset in the configurator, it would have generated correct positions to begin with.

Torin

I thought I did, I will double check that bit later and report my findings. Thanks!