Mesh Bed Probing issues



  • When I use the G29 command to probe my bed, I get some strange behavior on my X axis. I think it may have something to so with my the way I have my X axis set up. It is a dual head printer so when X is homed, the left nozzle is not over the board. I have tried to configure that in the config.g file but I may not have it right.

    When the probing starts, the head moves up to Z40 and X35. Then the X moves toward the endstop and tried to move past it. It then probes the bed but I don't think the X readings in Web Control are accurate. I had to reduce the right parameter for probing so the head didn't move past the end of the bed on that side.

    When it's done probing, it tries to move past my X endstop again.

    I do get a map, I haven not tried to print with it yet so I don't know how coordinated will line up.

    I'm running with firmware 1.20. Here is my config.g file.

    ; Configuration file for Mini Kossel kit from Think3DPrint3D for testing Duet WiFi

    ; Communication and general
    M111 S0 ; Debug off
    M550 PNCC1701 ; Machine name and Netbios name (can be anything you like)
    M551 Preprap ; Machine password (used for FTP)
    ;*** If you have more than one Duet on your network, they must all have different MAC addresses, so change the last digits
    M540 P0xBE:0xEF:0xDE:0xAD:0xFE:0xED ; MAC Address
    ;*** Wifi Networking
    M552 S1 ; Enable WiFi

    M555 P2 ; Set output to look like Marlin
    M575 P1 B57600 S1 ; Comms parameters for PanelDue

    G21 ; Work in millimetres
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    ; Axis and motor configuration
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S1 ; Drive 1 goes forwards
    M569 P2 S1 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes forwards
    M569 P4 S1 ; Drive 4 goes forwards
    M574 X1 Y1 Z1 S1 ; set endstop configuration (all endstops at high end, active high)
    ;*** The homed height is deliberately set too high in the following - you will adjust it during calibration
    ;M665 R105.6 L215.0 B85 H240 ; set delta radius, diagonal rod length, printable radius and homed height
    M666 X0 Y0 Z0 ; put your endstop adjustments here, or let auto calibration find them
    M350 X16 Y16 E16 I1 ; Set 16x microstepping with interpolation
    ;M92 X160.421 Y162.31 Z6437.16814 ;Set axis steps/mm
    M92 X159.90952 Y159.704907 Z6437.16814 ;Set axis steps/mm
    M906 X1100 Y1800 Z1000 E1000 I60 ; Set motor currents (mA) and increase idle current to 60%
    M201 X300 Y300 Z15 E30 ; Accelerations (mm/s^2)
    M203 X15000 Y15000 Z100 E600 ; Maximum speeds (mm/min)
    M566 X2000 Y2000 Z30 E30 ; Maximum instant speed changes mm/minute
    M208 X250 Y270 Z270

    ; Thermistors
    M305 P0 T100000 B3950 R4700 H30 L0 ; Put your own H and/or L values here to set the bed thermistor ADC correction
    M305 P1 T100000 B4388 R4700 H0 L0 ; Put your own H and/or L values here to set the first nozzle thermistor ADC correction
    M305 P2 T100000 B4388 R4700 H0 L0 ; Put your own H and/or L values here to set the second nozzle thermistor ADC correction
    M570 S180 ; Hot end may be a little slow to heat up so allow it 180 seconds

    ; Fans
    M106 P2 H-1 ; disable thermostatic mode for fan 1
    ;M106 P2 T50 H1
    M106 P1 T50 H1

    ; Tool definitions
    M563 P0 D0 H1 F2 ; Define tool 0
    G10 P0 S0 R0 ; Set tool 0 operating and standby temperatures
    ;*** If you have a single-nozzle build, comment the next 2 lines
    M563 P1 D1 H2 F2 ; Define tool 1
    G10 P1 S0 R0 X33 Y-1.725 ; Set tool 1 operating and standby temperatures
    M92 E300:300 ; Set extruder steps per mm

    ; Z probe and compensation definition
    ;*** If you have a switch instead of an IR probe, change P1 to P4 in the following M558 command
    ;M558 P1 X0 Y0 Z0 ; Z probe is an IR probe and is not used for homing any axes
    M558 P1 T1000
    G31 X-35 Y0.0 Z0.1 P500 ; Set the zprobe height and threshold (put your own values here)
    M557 X5:200 Y10:250 S20 ;Mesh Bed Definition

    ;*** If you are using axis compensation, put the figures in the following command
    ;M556 S78 X0 Y0 Z0 ; Axis compensation here

    M208 S1 X0 Y0 Z-0.2 ; set minimum Z
    ;
    T0 ; select first hot end


  • administrators

    @bbriggstkd said in Mesh Bed Probing issues:

    When I use the G29 command to probe my bed, I get some strange behavior on my X axis. I think it may have something to so with my the way I have my X axis set up. It is a dual head printer so when X is homed, the left nozzle is not over the board. I have tried to configure that in the config.g file but I may not have it right.

    When the probing starts, the head moves up to Z40 and X35. Then the X moves toward the endstop and tried to move past it. It then probes the bed but I don't think the X readings in Web Control are accurate. I had to reduce the right parameter for probing so the head didn't move past the end of the bed on that side.

    This line:

    M208 S1 X0 Y0 Z-0.2 ; set minimum Z

    sets minimum X to zero, meaning that at the homed position the head reference point is at X=0. You have chosen the head reference point to be the tool 0 nozzle, because you haven't specified any offsets for it. If that is the left nozzle (which seems likely, because the other tool has a positive X offset), then the homed position isn't at X=0, it's at some negative value of X.

    Your G31 line has a negative probe offset in the X parameter, meaning that the probe is in the -X direction from the head reference point. Is that correct?



  • I don't understand what you are saying. Tool 0 is my left nozzle, but when it's homes, it would be at 0. Why do you say it would be at some negative value of 0? My right nozzle, Tool 1 would then be at 33 when the head is homed.

    I reset my G31 to X0.0. I had been trying to see if it had something to do with the dual extruder. It still tries to go past my end stop. The sensor is over Tool 0 so when the head is homed, the sensor should be at 0 also.


  • administrators

    @bbriggstkd said in Mesh Bed Probing issues:

    It is a dual head printer so when X is homed, the left nozzle is not over the board

    I was assuming that you have a conventional X endstop switch that triggers right at the limit of motion at the low-X end of the axis. You said:

    It is a dual head printer so when X is homed, the left nozzle is not over the board

    I presume you meant the left nozzle is not over the bed. Assuming that you want X=0 to be the edge of the bed, this means that the X homing position has to be at negative X.



  • Ok, I see what you are getting at but I have my X- off the bed and I make sure my print doesn't try to extrude in the air.

    So, that being said. Why does the head try to move past the end stop?


  • administrators

    What type of Z probe does your machine have? If it is not a type that needs to be deployed before use, check whether you have deployprobe.g and retractprobe.g files in /sys on the SD card, and if so, delete them.



  • I have the mini differential IR Height sensor. I'll try removing those files and see what happens. I checked and they are there.


 

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