MCU 'mcu' shutdown: Rescheduled timer in the past * maybe a rotation_distance problem(

General Discussion
1

I updated my old cartesian printer to the last Kippler version + Octoprint starting from scratch.
I calculated ratoation distance for X Y Z from my previous old config:
X step_distance: .00625 → rotation_distance: 20
Y step_distance: .00625 → rotation_distance: 20
Z step_distance: .000156 → rotation_distance: 5

the problem is if I use 0.5 on Z axis I receive the MCU ‘mcu’ shutdown error.
I calculated the values also from my previous Marlin firmware and are ok. So where I am wrong?

Marlin was:
“Xstepspermm”: 160,
“Ystepspermm”: 160,
“Zstepspermm”: 6400,
“E0stepspermm”: 1240,

My config till now

[stepper_x]
step_pin: PF0
dir_pin: PF1
enable_pin: !PD7
microsteps: 16
rotation_distance: 20
endstop_pin: ^PE5
position_endstop: -6
position_min: -6
position_max: 228
homing_speed: 50

[stepper_y]
step_pin: PF6
dir_pin: !PF7
enable_pin: !PF2
microsteps: 16
rotation_distance: 20
endstop_pin: ^PJ1
position_min: -27
position_endstop: -27
position_max: 340
homing_speed: 50

[stepper_z]
step_pin: PL3
dir_pin: PL1
enable_pin: !PK0
microsteps: 16
rotation_distance: 0.5
endstop_pin: probe:z_virtual_endstop
position_max: 266
homing_speed: 20


[extruder]
step_pin: PA4
dir_pin: PA6
enable_pin: !PA2
microsteps: 16
rotation_distance: 33.500
nozzle_diameter: 0.500
filament_diameter: 3.500
heater_pin: PB4
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PK5
control: pid
pid_Kp: 22.2
pid_Ki: 1.08
pid_Kd: 114
min_temp: 0
max_temp: 210

[heater_bed]
heater_pin: PH3
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PK6
control: watermark
min_temp: 0
max_temp: 110

[mcu]
serial: /dev/ttyACM0

[printer]
kinematics: cartesian
max_velocity: 500
max_accel: 3000
max_z_velocity: 15
max_z_accel: 30



[bltouch]
sensor_pin: PD3
control_pin: PB5
x_offset: 0
y_offset: -37
z_offset: 1.8
sample_retract_dist: 6
samples: 3
speed: 2




[safe_z_home]
home_xy_position: 100, 100 # Change coordinates to the center of your print bed
speed: 20
z_hop: 5                # Move up 10mm
z_hop_speed: 5

Log attached.
My hardware Arduino Mega 2560
Z axis belt pitch pitch 2mm with 20 teeth pulley
NEMA17 1.8° step

klippy.log (211.0 KB)

2

You may reduce the z-axes homing speed.
With your settings the stepper has to produce 40 revolutions per second.
Try with 5 or 2 mm/sec z_homing_speed

On the other hand:

and this:

rotation_distance = <belt_pitch> * <number_of_teeth_on_pulley>

You should have a z_rotation_distance of 40, not 0.5
In that case, a z_homing_speed of 50 is ok

1 Like
3

Thank you very much for your answer. 0.5 is the right rotation _distance, maybe I don’t remember correctly the hardware spec, this is my very first printer unused for 3 years that I want to give to my son’s school, this is the reason I trying to update it.

So solved the problem but I am missing something now i corrected the z home speed as follow

[safe_z_home]
home_xy_position: 100, 100 # Change coordinates to the center of your print bed
speed: 4
z_hop: 5                # Move up 10mm
z_hop_speed: 5

Al the homing speed are paragonable to the one I had before the update , except one.
After I made X and Y home and I go for Z home the hotend move from X0 to X100 is very very slow ( 10 second for 10 cm)

This is a video

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4

Homing may be slow to avoid crashing into the endstop

5

The speed setting for safe_z_home is the XY travel speed. You’ve configured it for 4mm/s which is why it’s moving so slow. Change it back to the default of 50 to get reasonable movement speeds during homing.

If you want to control the speed of the Z axis during homing, you need to change homing_speed in your stepper_z section.

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6

One other note, I would use a larger z hop with a bltouch. The pin is very close to hitting the bed when deployed in the video, and it will cause an error if that happens.

7

Thank you very much guys! Problem solved, now I can proceed with the configuration

1 Like