Gcode override max_z_velocity

General Discussion
1

I’ve installed klipper on to my raspberry to control a skr 1.3. I followed the Configuration reference, and it seems to be working fine, but when it executes the “G1 z15.0 f6000” the z steppers stall. If I change it to “G1 z15.0 f200” it works fine. I assume that the gcode is overriding the max_z_velocity that is set to 25. This specific gcode runned fine in this printer before klipper, so I know is not it. What am I missing?

This file contains common pin mappings for the BIGTREETECH SKR V1.3

board. To use this config, the firmware should be compiled for the

LPC1768.

See docs/Config_Reference.md for a description of parameters.

[stepper_x]
step_pin: P2.2
dir_pin: !P2.6
enable_pin: !P2.1
microsteps: 16
rotation_distance: 80
endstop_pin: !P1.29 # P1.28 for X-max
position_endstop: 0
position_min: 0
position_max: 200
homing_speed: 50
full_steps_per_rotation: 400

[stepper_y]
step_pin: P0.19
dir_pin: !P0.20
enable_pin: !P2.8
microsteps: 16
rotation_distance: 80
endstop_pin: !P1.27 # P1.26 for Y-max
position_endstop: 0
position_min: 0
position_max: 200
homing_speed: 50
full_steps_per_rotation: 400

[stepper_z]
step_pin: P0.22
dir_pin: P2.11
enable_pin: !P0.21
microsteps: 16
rotation_distance: 4
endstop_pin: !P1.25 # P1.24 for Z-max
position_endstop: 0
position_max: 300
full_steps_per_rotation: 400

[stepper_z1]
step_pin: P0.1
dir_pin: P0.0
enable_pin: !P0.10
microsteps: 16
rotation_distance: 4
full_steps_per_rotation: 400
#endstop_pin: P1.24
#position_endstop: 0.5
#position_max: 400
#…

[extruder]
step_pin: P2.13
dir_pin: P0.11
enable_pin: !P2.12
microsteps: 16
rotation_distance: 15.5
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: P2.7
sensor_type: EPCOS 100K B57560G104F
sensor_pin: P0.24
control: pid
pid_Kp: 22.2
pid_Ki: 1.08
pid_Kd: 114
min_temp: 0
max_temp: 260
full_steps_per_rotation: 400
max_extrude_only_distance: 50

[heater_bed]
heater_pin: P2.5
sensor_type: ATC Semitec 104GT-2
sensor_pin: P0.23
control: watermark
min_temp: 0
max_temp: 130

[fan]
pin: P2.3

[mcu]
serial: /dev/serial/by-id/usb-Klipper_lpc1768_1D500017E01435AE8801ED52841E00F5-if00

[printer]
kinematics: cartesian
max_velocity: 200
max_accel: 2000
max_z_velocity: 25
max_z_accel: 100

########################################

TMC2208 configuration

########################################

For TMC2208 UART

1) Remove all of the jumpers below the stepper drivers

2) Place jumpers on the red pin headers labeled XUART (XUART, YUART etc.)

[tmc2208 stepper_x]
uart_pin: P1.17
run_current: 0.800
stealthchop_threshold: 999999

[tmc2208 stepper_y]
uart_pin: P1.15
run_current: 0.800
stealthchop_threshold: 999999

[tmc2208 stepper_z]
uart_pin: P1.10
run_current: 0.650
stealthchop_threshold: 999999

[tmc2208 stepper_z1]
uart_pin: P1.1
run_current: 0.650
stealthchop_threshold: 999999

[tmc2208 extruder]
uart_pin: P1.8
run_current: 0.800
stealthchop_threshold: 999999

########################################

TMC2130 configuration

########################################

For TMC SPI

1) Place jumpers on all the red pin headers under the stepper drivers

2) Remove jumpers from the red pin headers labeled XUART (XUART, YUART etc.)

#[tmc2130 stepper_x]
#cs_pin: P1.17
#spi_software_miso_pin: P0.5
#spi_software_mosi_pin: P4.28
#spi_software_sclk_pin: P0.4
##diag1_pin: P1.29
#run_current: 0.800
#stealthchop_threshold: 999999

#[tmc2130 stepper_y]
#cs_pin: P1.15
#spi_software_miso_pin: P0.5
#spi_software_mosi_pin: P4.28
#spi_software_sclk_pin: P0.4
##diag1_pin: P1.27
#run_current: 0.800
#stealthchop_threshold: 999999

#[tmc2130 stepper_z]
#cs_pin: P1.10
#spi_software_miso_pin: P0.5
#spi_software_mosi_pin: P4.28
#spi_software_sclk_pin: P0.4
##diag1_pin: P1.25
#run_current: 0.650
#stealthchop_threshold: 999999

#[tmc2130 extruder]
#cs_pin: P1.8
#spi_software_miso_pin: P0.5
#spi_software_mosi_pin: P4.28
#spi_software_sclk_pin: P0.4
##diag1_pin: P1.28
#run_current: 0.800
#stealthchop_threshold: 999999

#[tmc2130 extruder1]
#cs_pin: P1.1
#spi_software_miso_pin: P0.5
#spi_software_mosi_pin: P4.28
#spi_software_sclk_pin: P0.4
##diag1_pin: P1.26
#run_current: 0.800
#stealthchop_threshold: 999999

########################################

EXP1 / EXP2 (display) pins

########################################

[board_pins]
aliases:
# EXP1 header
EXP1_1=P1.30, EXP1_3=P1.18, EXP1_5=P1.20, EXP1_7=P1.22, EXP1_9=,
EXP1_2=P0.28, EXP1_4=P1.19, EXP1_6=P1.21, EXP1_8=P1.23, EXP1_10=<5V>,
# EXP2 header
EXP2_1=P0.17, EXP2_3=P3.26, EXP2_5=P3.25, EXP2_7=P1.31, EXP2_9=,
EXP2_2=P0.15, EXP2_4=P0.16, EXP2_6=P0.18, EXP2_8=, EXP2_10=
# Pins EXP2_1, EXP2_6, EXP2_2 are also MISO, MOSI, SCK of bus “ssp0”

See the sample-lcd.cfg file for definitions of common LCD displays.

2

Klipper does limit z velocity. F200 is only 3.33mm/s, so it’s not surprising that it works. You simply need to further reduce max_z_velocity to 10 or 15.

3

That solved it, thanks a lot.
But this problem brought me another question. Since this problem was occurring after the z homing, and it skipped a lot of steps going up, when it came down would ignore the endstop and crash horrible into the build plate. I don’t have any homing sensor, just a old fashion switch, is there any way to insure that the hot end never goes below the endstop?

4

Klipper only monitors endstops during homing, so the only way to prevent this is to make sure the motor doesn’t skip steps. As long as you use a max_z_velocity that doesn’t skip steps you shouldn’t have this problem.

5

Thanks again, you saved me a lot of time.