M702.cfg

# See: https://reprap.org/wiki/G-code#M702:_Unload_filament
[gcode_macro M702]
description: Unload filament compatible command
gcode:
    # Setup fallback defaults
    {% set default_u = 100 %}                                   # set defualt extrude length

    # Try load bowden tube length from saved variables
    {% if 'save_variables' in printer %}                        # check if save variables is defined
        {% set svv = printer.save_variables.variables %}        # get variables object
        {% if 'bowden_length' in svv %}                         # check if bowden length is defind
            {% set default_u = svv.bowden_length %}             # and load it if it exist
        {% endif %}
    {% endif %}

    # Get command parameters
    {% set p    = params.P|default(8)|float %}
    {% set p_f  = params.PF|default(180)|float %}
    {% set i    = params.I|default(30)|float %}
    {% set i_f  = params.IF|default(180)|float %}
    {% set u    = params.U|default(default_u)|float %}
    {% set u_f  = params.UF|default(360)|float %}

    {% if printer.idle_timeout.state == "Printing" and not printer.pause_resume.is_paused %}
        {action_respond_info("This command cannot be used while printing")}
    {% elif printer.extruder.temperature < 170 %}
        {action_respond_info("Extruder temperature too low")}
    {% else %}
        SAVE_GCODE_STATE NAME=M702_state
        M83                                                     # relative positioning
        {% if p > 0.0 %}
            G1 E{p} F{p_f}
        {% endif %}
        {% if i > 0.0 %}
            G1 E-{i} F{i_f}
        {% endif %}
        {% if u > 0.0 %}
            G1 E-{u} F{u_f}
        {% endif %}
        RESTORE_GCODE_STATE NAME=M702_state MOVE=0
    {% endif %}