Klipper: Configuration for Anycubic Kossel 218mm rod version

Hello,

I'm trying to configure klipper for my anycubic kossel. The biggest problem is translating the geometry from marlin 1.1.8 to the klipper configuration files. Does anyone know how to calculate the values from a working marlin config?
This is my marlin config:

  // Print surface diameter/2 minus unreachable space (avoid collisions with vertical towers).
  #define DELTA_PRINTABLE_RADIUS 90 // mm

  // Center-to-center distance of the holes in the diagonal push rods.
  #define DELTA_DIAGONAL_ROD 218.0 // mm

  // height from z=0 to home position
  #define DELTA_HEIGHT 330.16 // get this value from auto calibrate

  #define DELTA_ENDSTOP_ADJ { -1.43, -0.51, 0.00 } // get these from auto calibrate

  // Horizontal distance bridged by diagonal push rods when effector is centered.
  #define DELTA_RADIUS 102.53 //mm  Get this value from auto calibrate

  // Trim adjustments for individual towers
  // tower angle corrections for X and Y tower / rotate XYZ so Z tower angle = 0
  // measured in degrees anticlockwise looking from above the printer
  #define DELTA_TOWER_ANGLE_TRIM { -0.15, -0.03, 0.18 } // get these values from auto calibrate

This is the corresponding part of my printer.cfg

[stepper_a]
step_pin: ar54
dir_pin: !ar55
enable_pin: !ar38
step_distance: .0125
endstop_pin: ^ar2
homing_speed: 50
position_endstop: 328.73 # 330.16 - 1.43
#   Distance (in mm) between the nozzle and the bed when the nozzle is
#   in the center of the build area and the endstop triggers. This
#   parameter must be provided for stepper_a; for stepper_b and
#   stepper_c this parameter defaults to the value specified for
#   stepper_a.
arm_length: 320.53              # DELTA_DIAGONAL_ROD + DELTA_RADIUS
#   Length (in mm) of the diagonal rod that connects this tower to the
#   print head. This parameter must be provided for stepper_a; for
#   stepper_b and stepper_c this parameter defaults to the value
#   specified for stepper_a.
angle: 209.85           # 210 - 0.15
#   This option specifies the angle (in degrees) that the tower is
#   at. The default is 210 for stepper_a, 330 for stepper_b, and 90
#   for stepper_c.

Are these assumptions correct?
- arm_length = DELTA_DIAGONAL_ROD + DELTA_RADIUS = 218mm + 102.53mm
- endstop adjustments can not be entered directly. Instead adjust the endstop
-> position_endstop = DELTA_HEIGHT + DELTA_ENDSTOP_ADJ = 330.16mm + (-1.43mm)
- The tower trim has to be calculated manually for each tower, i.e.
angle = {210, 330, 90} + DELTA_TOWER_ANGLE_TRIM {X,Y,Z}


This printer doesn't have a heated bed. Without the heater section the startup fails:

Config error
Traceback (most recent call last):
  File "/home/pi/klipper/klippy/klippy.py", line 244, in _connect
    cb('ready')
  File "/home/pi/klipper/klippy/extras/heater_fan.py", line 24, in printer_state
    self.printer, self.heater_name)
  File "/home/pi/klipper/klippy/extruder.py", line 261, in get_printer_heater
    return printer.lookup_object(name)
  File "/home/pi/klipper/klippy/klippy.py", line 164, in lookup_object
    raise self.config_error("Unknown config object '%s'" % (name,))
Error: Unknown config object 'heater_bed'

- Is there an easy way around it?

There is an Anycubic Kossel configuration file in the master branch now:

https://github.com/KevinOConnor/klipper/blob/master/config/printer-anycubic-kossel-2016.cfg
https://github.com/KevinOConnor/klipper/pull/378

Here are the Klipper settings you need to adjust with the corresponding Marlin defines in place of the values.

[stepper_a]
position_endstop: DELTA_HEIGHT
arm_length: DELTA_DIAGONAL_ROD

[printer]
delta_radius: DELTA_RADIUS

DELTA_PRINTABLE_RADIUS is not implemented in Klipper yet https://github.com/KevinOConnor/klipper/issues/379

The DELTA_ENDSTOP_ADJ and DELTA_TOWER_ANGLE_TRIM should be calculated by Klipper's own auto calibration - see the [delta_calibrate] section.

Thanks!

I've switched over to a MKS SBase v1.3. And I've realized, that it's impossible to get clean prints with Octoprint. I think the cause is that the bandwidth and latency of the usb-connection is just not good enough which results in small pauses. So I've blobs all over my prints. I can fix this by printing from SDcard. But then I have other problems like the ringing DVR8825 stepper drivers. Maybe Klipper is actually the way to go long term because it can cope with the USB bottleneck.

Quote
avion23
Maybe Klipper is actually the way to go long term because it can cope with the USB bottleneck.

I doubt that, Klipper has other bottleneck – the UART interface between the host and MCU/s. With all peripherals like LCD, fans, step motor configs etc. which communication is going through the UART for me this is quite of an issue. Also Github issue #133 - laser engraving …