Homing delta not working, possible configuration issue?

  • I am configuring my new delta printer, a 1M tall, 500mm side three-tower. I have upgraded my Duet WiFi to 1.20, and my paneldue is still running 1.16. Right now I am just working out the kinematics of the machine, so I have not connected the fans, extruder motor, extruder heater, thermistor, bed heater, or the IR probe.

    Since I will be using an IR probe, I deleted the files related to deploying the probe as documented in 1.19's Changelog.

    When I press the "Home" button on the PanelDue, or send G28, the three delta carriages move up about 1-2mm, and then nothing else happens. Every G28/Home Press moves them up a little bit more, but the carriages do not act as they should. I am using Kysan bipolar 1.8 degree steppers @24V, 16 microsteps, 48T pulleys, and GT2 belts. My configured axis steps/mm is therefore 33.33 steps per mm. (200*16)/48/2

    As far as I can tell, the steppers are moving smoothly and quietly, in the correct direction… I'm just not seeing the right behavior.

    The configuration files in sys:

    My config.g is:

    M550 PMartinDelta		; 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:0xa3:0x22 	; 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 X2 Y2 Z2 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 L256 R431.8 H500 B155 X0 Y0	; 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 X33.33 Y33.33 Z33.33					; Set axis steps/mm
    M906 X1200 Y1200 Z1200 E800 I60		; Set motor currents (mA) and increase idle current to 60%
    M201 X1000 Y1000 Z1000 E1000		; Accelerations (mm/s^2)
    M203 X20000 Y20000 Z20000 E3600		; Maximum speeds (mm/min)
    M566 X1200 Y1200 Z1200 E1200		; Maximum instant speed changes mm/minute
    ; 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 B3974 R4700 H30 L0	; Put your own H and/or L values here to set the first nozzle thermistor ADC correction
    ; M570 S180				; Hot end may be a little slow to heat up so allow it 180 seconds
    ; Fans
    ; M106 P1 T50 H1				; Fan 1 turns on at 50C, cools hotend
    ; M106 P2 H-1
    ; M106 P3 H-1
    ; Tool definitions
    ; M563 P0 D0 H1                       	; 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                      	; Define tool 1
    ;G10 P1 S0 R0                       	; Set tool 1 operating and standby temperatures
    ; M92 E663:663                       	; 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
    G31 X0 Y0 Z4.80 P500			; Set the zprobe height and threshold (put your own values here)
    ;*** If you are using axis compensation, put the figures in the following command
    M556 S78 X0 Y0 Z0                   	; Axis compensation here
    M208 S1 Z-0.2				; set minimum Z
    ;T0					; select first hot end

    My homedelta.g is:

    ; Homing file for RepRapFirmware on Mini Kossel
    G91							; use relative positioning
    G1 S1 X500 Y500 Z500 F2500	; move all carriages up 320mm, stopping at the endstops
    G1 S2 X-3 Y-3 Z-3			; move all carriages down 3mm
    G1 S1 X6 Y6 Z6 F250			; move carriages slowly up 6mm, stopping at the endstops
    G1 Z-5 F2000				; down a few mm so that we can centre the head
    G90							; back to absolute positioning
    G1 X0 Y0 F2000				; centre the head and set a reasonable feed rate

  • D'oh!

    Fiigured it out… two of the axes endstops were swapped ( Y/Z ) and didn't go to the corresponding motors., and because I was using Maker Mechanical 1.2 endstops, the logic was reversed ( S0 vs S1 )

    Now that is fixed, I still have one more mysterious issue. I can run G28 and the machine homes, BUT afterwards I can't get any G0/G1 moves to work, and there are no errors on the console of the paneldue.

    I go into relative mode, then try to instruct the machine to drop down 50mm :

    G1 Z-10 F2000

    Nada. No errors, just no movement.

  • Follow-up

    I can do G92 X0 Y0 Z360 ( the actual height of my towers to the bed ) and it works
    I can do G91 and run the TOWERS.. i.e. ( G91 S1 X-50 Y-50 Z-50 F2500 ) and the towers move

    I just can't do G91, then G1 Z-10 F2000 for example … no movement, but also no errors

  • administrators

    There is an error in your M665 command. The combination of L and R you have specified is physically impossible. Your R (delta radius) parameter looks to me to be about double what it should be, perhaps more than double.

  • Increase the X, Y and Z in G1 S1 X500 Y500 Z500 F2500 in your homedelta to 800+ so you don't have to double tap home when you are stretched out on the build plate.


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