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MDM Module Filament Clog Detection

Feature Introduction​

The FLY-LLL PLUS Buffer can be used in conjunction with the FLY-MDM Filament Runout/Clog Sensor to achieve real-time monitoring and automatic handling of extruder clog status.

Core Features​

  • Clog Detection: The MDM module monitors the buffer's filament status to detect clogs.
  • Unified Runout/Clog Handling: Runout detection is also handled by the MDM module, with signals sent via the buffer.

Important Note: When using the MDM module, all runout/clog detection signals are sent to the mainboard via the buffer. The mainboard cannot distinguish whether the signal originates from a runout or a clog.

Firmware Requirements​

  • The buffer firmware version must be V1.1.5 or higher.

Hardware Wiring​

1. Connecting the MDM Module to the Buffer​

The MDM module communicates directly with the buffer to detect clog status:

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2. Connecting the Buffer to the Mainboard​

The mainboard sends signals to the buffer.

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3. Buffer Filament Runout Detection Wiring​

The buffer's runout detection must be connected to the mainboard, otherwise it will not function properly.

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Specific Connection Method:

Buffer PinFunction DescriptionConnection Suggestion
STEPExtruder Stepper Signal MonitoringConnect to a free PWM, RGB, or 12864 interface on the mainboard.
DIRExtruder Direction Signal MonitoringConnect to a free endstop interface on the mainboard.

Tip: The servo port of a BL-Touch can also be used for STEP signal monitoring.

Klipper Configuration​

Pre-configuration Preparation​

Before adding the MDM module configuration, ensure the following are correctly configured:

  • Basic extruder configuration
  • Basic buffer functionality configuration
  • Note: Filament runout detection now follows the path: MDM module → Buffer → Mainboard.

1. Buffer Monitor Configuration (for Clog Detection)​

Add the following configuration to the Klipper configuration file (e.g., printer.cfg) to monitor the extruder status:

[extruder_stepper buffer_monitor]
extruder: extruder           # Name of the associated main extruder
step_pin: PE10               # Replace with the actual pin connected to buffer PA5
dir_pin: PD4                 # Replace with the actual pin connected to buffer PB11
rotation_distance: 17.472    # Replace with the actual value for your extruder
gear_ratio: 50:10            # Replace with the actual gear ratio for your extruder
microsteps: 16               # Replace with the actual microsteps for your extruder
full_steps_per_rotation: 200 # Standard stepper motor is 200 steps/revolution

Complete Configuration Example​

# Main Extruder Configuration
[extruder]
step_pin: PB13
dir_pin: PB12
enable_pin: !PB14
microsteps: 16
rotation_distance: 17.472
gear_ratio: 50:10
nozzle_diameter: 0.4
filament_diameter: 1.75
heater_pin: PA1
sensor_type: ATC Semitec 104GT-2
sensor_pin: PC1
control: pid
pid_Kp: 21.527
pid_Ki: 1.063
pid_Kd: 108.982
min_temp: 0
max_temp: 280

[extruder_stepper buffer_monitor]
extruder: extruder
step_pin: PE10      # Connected to buffer PA5
dir_pin: PD4        # Connected to buffer PB11
rotation_distance: 17.472
gear_ratio: 50:10
microsteps: 16
full_steps_per_rotation: 200

[filament_switch_sensor Material_breakage_detection]
pause_on_runout: true
switch_pin: ^PA0   # Please replace with the pin you actually use
runout_gcode:
    PAUSE
    RESPOND MSG="Filament runout detected, print paused"
insert_gcode:
    RESPOND MSG="Filament inserted, preparing to resume print"
event_delay: 2.0    # Event trigger delay (seconds)
pause_delay: 2.0     # Pause command delay (seconds)
debounce_delay: 2.0  # Debounce delay (seconds)

Buffer Configuration​

Important Notes
  • If the extruder configuration does not have gear_ratio, change both Drive Gear Teeth and Driven Gear Teeth to 1.
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Parameter Description​

Function DescriptionConfiguration Command (Please enter in the serial tool)Default ValueUnitNotes
View all current parameters
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--Send command to read all current configurations.
Set motor pulse count
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916-Set the number of pulses required for the motor to move per millimeter.
Set encoder detection distance
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1.73mmSet the filament movement distance represented by each encoder signal.
Set run timeout duration
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60000msSet the auto-stop time in an untriggered state to prevent continuous extrusion.
Set error scaling factor
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2.0-Allowed error = encoder value X scale value.
Example: 1.73 * 2.0 = 3.46 mm
Set speed control command
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260mmSet the buffer operating speed, maximum 600 (revolutions/minute), firmware needs to be updated to V1.1.1

Operation Notes:

  1. Command Format: In the "Configuration Command" column of the above table, a full line of command (e.g., steps 916) is the content that needs to be fully entered.
  2. Sending Method: Enter the command in the sending area of the serial assistant, then click Send.
  3. Auto Save: Once the command is sent successfully, the parameter will take effect immediately and be automatically saved, no additional save operation is required.
  4. Confirm Configuration: After modifying any parameter, send the info command to query all current parameters to verify whether the configuration is correct.
Important Notes
  • After remembering the set parameters, you can configure the buffer via the link below.
  • Buffer Configuration

Function Testing​

1. Connection Test​

  1. Complete the connection between the MDM module and the buffer.
  2. Complete the signal wire connection between the buffer and the mainboard.
  3. Ensure all connections are secure.

2. Complete Process Test​

  1. Start a test print.
  2. Simulate a clog situation (operate with caution).
  3. Observe:
    • Whether the MDM module detects the issue.
    • Whether the buffer forwards the signal.
    • Whether the mainboard receives the signal.
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