Stepper motors riddle

General Discussion
1

Hi. Maybe I’m just being stupid but I can’t find what’s wrong. I’m trying to convert my V-King coreXY with three independent z-motors to klipper.
With the Z-motors disconnected I can home x and y beautifully.
When I hook up the (geared) Z- stepper motors to my Octopus Pro board homing x and y gives a loud screeching noise for about three seconds before homing normally (and silently)
I don’t know in which direction to search.

2

My guess is you’re using some type of homing override that lifts the Z axis before homing, and the noise is your Z steppers.

ttps://www.klipper3d.org/FAQ.html#i-converted-my-config-from-marlin-and-the-xy-axes-work-fine-but-i-just-get-a-screeching-noise-when-homing-the-z-axis

3

I already saw that and tried lowering my acceleration but no cigar. I’ll go over the checks again.

4

Acceleration is not the issue. You need to limit velocity for the z axis.

5

It’s at 5 right now. What should I try ?

6

If it’s still buzzing at 5, then I would check wiring. Verify coil pairs and check pinout of the board.

7

Ok, thank you. I’ll check.

8

They are correctly connected to my Octopus Pro. However, they are 1:27 geared steppers and maybe I made a mistake in the configuration :

[stepper_z]
step_pin: PF11
dir_pin: PG3
enable_pin: !PG5
microsteps: 16
rotation_distance: 1.48
gear_ratio: 27:1
endstop_pin: probe:z_virtual_endstop
position_max: 200
homing_positive_dir: false

[tmc2209 stepper_z] #Driver connector 2
uart_pin: PC6
##diag_pin: PG10
run_current: 0.800
stealthchop_threshold: 999999

This is the first of the three Z-steppers.

Could anybody confirm this is correct ?

9

I’m guessing the final output is a 20 tooth pulley based on your rotation distance, and this is your problem. Rotation distance is the final output, and gear ratio will make Klipper do the math internally. Right now you’re telling Klipper the motor needs to rotate 27 times to move the axis 1.48mm. Change the rotation distance to 40 if you do indeed have a 20 tooth pulley.

10

Yes, I managed to find that myself. The whining disappeared but one stepper is not working on my Octopus pro board.

11

You’ll need to check wiring and verify you have the driver in the correct socket. I can’t offer any more help.

12

Ok, thank you very much.