Power Loss Resume Function in Klipper

Overview

• The Power Loss Resume Function in Klipper refers to the ability to automatically restore the print state of Klipper after it has been powered off and then powered back on.
• This function can only be used with the FAST system.
• PI-V2 requires a KPPM power loss module to use this function.
• Not suitable for machines where the Z-axis may shift after a power outage.
• Introduction to KPPM

Configuration

Turn off power-off shutdown

Note

• To use the power failure resume function, you need to turn off the power-off shutdown.
• The power failure resume has an automatic shutdown function after saving the progress.
• Please make sure there is no other power connected to the host, otherwise it will not be able to start up

• Enter the device's IP address in the browser's address bar, for example: http://192.168.6.179

• Enter the configuration page

  • Open the device ip address in the browser, for example: http://192.168.1.2/
  • For fluidd, as shown on the left in the figure, uncheck -> filter hidden files and folders.
  • For mainsail, as shown on the right in the figure, check -> show hidden files.
  • At this point, you can see the .flyos-config folder, entering this folder will have the sys-config.conf file.
  • The sys-config.conf file is a soft link to the configuration file config.txt in the removable disk FlyOS-Conf.
  
  • Open the sys-config.conf file, find the configurations shutdown_pin_state and shutdown_pin=
  • Add # before these configurations
  • Then save -> close and restart
  

plr.cfg configuration file

Note

• Replace the : (PINS) in the configuration file with host:gpiochip1/gpio21

• In the printer configuration page, find the plr.cfg file.
• Empty its content, then paste the configuration below
• Configuration file content is as follows:

[mcu host]   
serial: /tmp/klipper_host_mcu

[power_loss_resume]
power_pin: (PINS)
is_shutdown: True # Whether to execute the shutdown operation, enabled by default
paused_recover_z: -2.0 # Z movement distance when resuming printing if paused, default is no movement
start_gcode:
    # Gcode executed before resuming printing
    # All parameters saved before power failure can be obtained through {PLR}
    # You can use M118 {PLR} to output all available parameters
    M118 Resuming print: {PLR.print_stats.filename}
    M118 Interruption position: X:[{PLR.POS_X}] Y:[{PLR.POS_Y}] Z:[{PLR.POS_Z}] E:[{PLR.POS_E}]
    M140 S{PLR.bed.target}      ; Set bed temperature
    M104 S{PLR.extruder.target-10}  ; Set extruder temperature
    M109 S{PLR.extruder.target-10}  ; Wait for extruder to reach set temperature
    G91                             ; Relative coordinates
    G1 Z2 F100                      ; Raise Z, prepare to zero X,Y
    G90                             ; Absolute coordinates
    G28 X Y                         ; Zero X Y
    M140 S{PLR.bed.target}          ; Set bed temperature
    M104 S{PLR.extruder.target}     ; Set extruder temperature
    M190 S{PLR.bed.target}          ; Wait for bed to reach set temperature
    M109 S{PLR.extruder.target}     ; Wait for extruder to reach set temperature
    M83                             ; Relative extrusion
    # G1 E0.5 F400                  ; Extrude a little
layer_count: 2 # Execute layer_change_gcode after resuming specified layers
layer_change_gcode:                
    # Gcode to execute after resuming {layer_count} layers
    M118 Resume print speed
    M106 S{PLR.fan_speed}             ; Turn on cooling fan
    M220 S{PLR.move_speed_percent}    ; Set requested speed percentage
    M221 S{PLR.extrude_speed_percent} ; Set requested extrusion speed percentage
shutdown_gcode:
    # Gcode executed before shutdown
    M118 Low power voltage, shutting down
    # M112 ; Emergency stop

Note

• The start_gcode macro in the above configuration file may need to be modified, specific modifications should be based on the actual machine.
• If you are using [homing_override], do not arbitrarily set the homing position in [homing_override]. The failure of power failure resume is not responsible.
• If you are using [gcode_macro _CLIENT_VARIABLE], find variable_custom_park_dz and set it to 0

• After saving the configuration file above

• Open the printer.cfg file, and add the following content at the beginning of the file:

  
  [include plr.cfg]
  

• Click save and restart in the top right corner.

• At this point, the Klipper power failure resume function has been configured.

Test

• Print any file, click the Emergency Stop button during printing to simulate a power failure.
• Click Firmware Restart again, wait for Klipper to connect normally.
• If a pop-up window appears on the web page or KlipperScreen, it indicates that the power failure resume function is working properly.
• Subsequently, you can continue to test real power failure situations.