klipper-macros/macros/print/homing.cfg

# HOME: home all axes and move to the bed centre
#
# Z always with Beacon contact (the nozzle touches the bed), also when the
# printer is already homed. Without METHOD=CONTACT, [beacon]
# home_method_when_homed = proximity homes a homed printer on the
# eddy-current model of an earlier print (other bed temperature, maybe
# another plate) without touching the bed and without recalibrating.
# Contact refuses a nozzle above 180C (contact_max_hotend_temperature).

[gcode_macro HOME]
gcode:
    G90
    G4 P2000
    _GUARD_ON PHASE=home_xy
    G28 X Y
    # Contact homing presses the nozzle on the bed: guard off
    _GUARD_OFF
    G28 Z METHOD=CONTACT CALIBRATE=1
    _GUARD_ON PHASE=home_lift
    G1 X175 Y175 Z10 F1200
    _GUARD_OFF

# _Z_CHECK: compare where Klipper thinks the nozzle is with what the Beacon
# measures (proximity), at X/Y (default the bed centre) and Z (default 3 mm,
# inside the model range 0.2-5 mm). Catches a Z that changed since the last
# homing (lost Z steps, gantry moved, much thermal drift) before the nozzle
# goes low; a difference above MAX stops the print. A wrong Beacon model
# fools both readings the same way, so this does not replace contact homing.
#
# BEACON_QUERY stores its reading in printer.beacon.last_sample. When it
# gives no new reading there, the check only warns, so a Beacon version
# without that field does not stop every print.
[gcode_macro _Z_CHECK]
description: Compare Klipper's Z with the Beacon reading at X Y Z (default 175 175 3), stop the print when they differ by more than MAX (default 0.5 mm)
gcode:
    {% set x = params.X|default(175)|float %}
    {% set y = params.Y|default(175)|float %}
    {% set z = params.Z|default(3)|float %}
    {% set max = params.MAX|default(0.5)|float %}
    {% if 'xyz' not in printer.toolhead.homed_axes %}
      _ERROR MSG="_Z_CHECK: printer not homed" DISPLAY="Z check: not homed"
    {% elif 'beacon' not in printer %}
      _WARN MSG="_Z_CHECK: no [beacon], check skipped"
    {% else %}
      {% set last = printer.beacon.last_sample %}
      {% set prev = last.time if last and last.time is defined else -1 %}
      SAVE_GCODE_STATE NAME=_z_check
      G90
      _GUARD_ON PHASE=z_check
      {% if printer.toolhead.position.z < z %}
        G1 Z{z} F600
      {% endif %}
      G1 X{x} Y{y} F12000
      G1 Z{z} F600
      _GUARD_OFF
      G4 P300
      BEACON_QUERY
      _Z_CHECK_EVAL MAX={max} PREV={prev}
      RESTORE_GCODE_STATE NAME=_z_check
    {% endif %}

# Separate macro: rendered after BEACON_QUERY has run. toolhead.position is
# the real nozzle height (gcode offset and mesh included).
[gcode_macro _Z_CHECK_EVAL]
description: Helper for _Z_CHECK: compare the BEACON_QUERY reading with the toolhead Z
gcode:
    {% set s = printer.beacon.last_sample %}
    {% set z = printer.toolhead.position.z %}
    {% set max = params.MAX|default(0.5)|float %}
    {% if not s or s.time is not defined or s.dist is not defined or s.time == params.PREV|default(-1)|float %}
      _WARN MSG="_Z_CHECK: BEACON_QUERY left no new reading in printer.beacon.last_sample, Z check skipped" DISPLAY="Z check skipped"
    {% elif s.dist is none %}
      _ERROR MSG="_Z_CHECK: Klipper Z={'%.2f' % z} but the Beacon reads nothing (more than 5 mm away or no model), print stopped" DISPLAY="Z check failed, print stopped"
    {% elif (s.dist - z)|abs > max %}
      _ERROR MSG="_Z_CHECK: Klipper Z={'%.3f' % z}, Beacon measures {'%.3f' % s.dist} mm (difference {'%.3f' % (s.dist - z)}, limit {max}), print stopped" DISPLAY="Z check failed, print stopped"
    {% else %}
      RESPOND MSG="Z check: Klipper Z={'%.3f' % z}, Beacon {'%.3f' % s.dist} mm, difference {'%.3f' % (s.dist - z)} (limit {max})"
    {% endif %}