Klipper Power Loss Resume Functionality

Overview

• The Klipper power loss resume function refers to the ability of Klipper to automatically restore its printing status after being powered off and then powered on again.
• This feature requires the use of a safety shutdown module.
• It is not applicable for machines where the Z-axis will move when power is lost.

Configuration

Disable Power-off Shutdown

Notice

• The power-off shutdown must be disabled; otherwise, the power loss resume function cannot be used.
• There is an automatic shutdown after saving progress in the power loss resume process.

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

• Access the configuration page

  • Open the device IP address in the browser, for example: http://192.168.1.2/
  • In fluidd, uncheck as shown on the left in the figure below -> Hide hidden files and folders.
  • In mainsail, check as shown on the right in the figure below -> Show hidden files.
  • You can now see the .flyos-config folder. Inside this folder, there is a sys-config.conf file.
  • The sys-config.conf file is a symbolic link to the config.txt file in the removable disk FlyOS-Conf.
  
  • Open the sys-config.conf file and locate the configurations shutdown_pin_state and shutdown_pin=.
  • Add a # before these configurations.
  • Then save and close, and restart the system.
  

plr.cfg Configuration File

• Find the plr.cfg file in the printer configuration page.

• Clear the content inside and paste the following configuration:

  [mcu host]   
  serial: /tmp/klipper_host_mcu
  
  [power_loss_resume]
  power_pin: !host:gpiochip0/gpio260 # Shutdown pin of the safety shutdown module connected to PA21 pin on the host machine
  is_shutdown: True # Whether to execute shutdown operation, default is enabled
  paused_recover_z: -2.0 # Z movement distance during recovery if paused at shutdown, default is no movement
  start_gcode:
      # G-code to run before resuming print
      # All parameters saved before power loss can be accessed via {PLR}
      # Use M118 {PLR} to output all available parameters
      M118 Start Resuming Print: {PLR.print_stats.filename}
      M118 Interrupt 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 until extruder reaches set temperature
      G91                             ; Relative coordinates
      G1 Z2 F100                      ; Lift Z, prepare for X,Y homing
      G90                             ; Absolute coordinates
      G28 X Y                         ; Home XY
      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 bit
  layer_count: 2 # Number of layers to resume before executing layer_change_gcode
  layer_change_gcode:                
      # G-code 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 extrude speed percentage
  shutdown_gcode:
      # G-code to run before shutdown
      M118 Low Power Voltage, Shutting Down
      # M112 ; Emergency stop
  

  Note

  • The macros in the start_gcode above may need modification based on the specific machine's situation.

• After saving the above configuration file,

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

  
  [include plr.cfg]
  

• Click the top-right "Save and Restart" button to apply the changes.

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

Testing

• Start printing any file. During the print process, click the "Emergency Stop" button to simulate a power outage.
• Click "Firmware Restart" again. Once Klipper reconnects normally,
• If a pop-up prompt appears on the webpage or KlipperScreen, it indicates that the power loss resume function is working correctly.
• Further testing with real power outages can be conducted afterward.