Stop using bdwidth while printing, work without it

bdwidth's motion reading stays at 0, its per-reading width compensation
made the flow jump between 77 and 119%, and a USB dropout shut down
Klipper. PRINT_START no longer enables it. _PRINT_CLEANUP,
BLOBIFIER_CHECKED and PURGE_UNTIL_EMPTY only send bdwidth commands when
[bdwidth fila_width_0] exists, and bdwidth_status reports present: False
with neutral values when it is not configured, so the section can be
removed from printer.cfg.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CLAUDE.md

@@ -11,10 +11,10 @@ Voron 2.4 350, Klipper + Moonraker + Mainsail on a Raspberry Pi 4
 5 lanes, Blobifier purge bucket, Beacon (Z homing and probing), Nitehawk-SB
 toolboard (USB), Leviathan mainboard as USB-CAN bridge, bd_pressure
 (load-check firmware, branch `load-check-extension` in
-`D:\Claude\bd_pressure-load-check\bd_pressure`), bdwidth (measures width and
-motion optically with a CCD; its motion reading stays at 0, so it runs width
-only (`ENABLE_WIDTH` in PRINT_START) and the purge check runs with
-`motion_check: False`; clogs and breaks are caught by AFC's buffer fault
+`D:\Claude\bd_pressure-load-check\bd_pressure`), bdwidth (CCD width/motion sensor on USB; switched off: its motion reading
+stays at 0, its width compensation made the flow jump 77-119% and a USB
+dropout once shut down Klipper. The macros work with or without
+`[bdwidth fila_width_0]`; clogs and breaks are caught by AFC's buffer fault
 detection, `filament_error_sensitivity`), iHeater chamber heater.
 
 ## Working with the printer

README.md

@@ -20,7 +20,7 @@ everything below, grouped by topic. Comment out what you do not use there.
 | `blobifier.cfg` | `BLOBIFIER`, `BLOBIFIER_CLEAN`, `BLOBIFIER_PARK`, `BLOBIFIER_SHAKE_BUCKET`, ...: purge bucket and nozzle brush for AFC (Turtleblobifier, heavily modified) | Blobifier hardware, AFC |
 | `blobifier_hw.cfg` | servo and bucket switch pins | — |
 | **print/** | | |
-| `print_start_end.cfg` | `PRINT_WARMUP`, `PRINT_START`, `PRINT_END` | Beacon, AFC, Blobifier, `HEAT_SOAK`, iHeater, bdwidth, bd_pressure PA macros |
+| `print_start_end.cfg` | `PRINT_WARMUP`, `PRINT_START`, `PRINT_END` | Beacon, AFC, Blobifier, `HEAT_SOAK`, iHeater, bd_pressure PA macros (bdwidth is no longer enabled while printing) |
 | `pause_resume.cfg` | `PAUSE`, `RESUME`, `CANCEL_PRINT`, `M600` (RESUME also handles a running `HEAT_SOAK`, and after a PAUSE purges 40 mm with `BLOBIFIER_CHECKED` first: a failed check keeps the print paused, `RESUME PURGE=0` skips the purge; CANCEL_PRINT runs the same cleanup as `PRINT_END`) | `heating/heat_soak.cfg`, `leds/`, `blobifier/`, `afc/purge_check.cfg` |
 | `filament.cfg` | `LOAD_FILAMENT`, `UNLOAD_FILAMENT` | — |
 | `homing.cfg` | `HOME` | — |
@@ -50,7 +50,7 @@ everything below, grouped by topic. Comment out what you do not use there.
 | File | For |
 |---|---|
 | `xy_drift.py` | `AFC_XY_SAFETY_CHECK`: measures lost XY steps from the stepper step counts at the endstop triggers (CoreXY). The toolhead position after homing cannot show lost steps. |
-| `bdwidth_status.py` | exposes bdwidth's motion counter and width to macros, and keeps a USB dropout of bdwidth (port: usb) from shutting down Klipper: the read is retried every 10 s and the port reopened |
+| `bdwidth_status.py` | exposes bdwidth's motion counter and width to macros (`present: False` with neutral values when no bdwidth is configured, so the macros also work without it), and keeps a USB dropout of bdwidth (port: usb) from shutting down Klipper: the read is retried every 10 s and the port reopened |
 | `bdpressure_check.py` | bd_pressure load check (`BDP_CHECK_START/STOP/QUERY`). Needs the load-check firmware from the bd_pressure `load-check-extension` branch; on stock firmware it reports "not available" and does nothing. |
 
 ### Scripts (`scripts/`)

extras/bdwidth_status.py

@@ -26,6 +26,9 @@
 #                    only starts reading on the first SET_BDWIDTH ... ENABLE
 #   linear_motion  - counts per mm (motion_linear_coefficient)
 #   sample_time    - seconds between sensor reads
+#   present        - False when no [bdwidth <sensor>] is configured; the
+#                    other fields then hold neutral defaults, so macros keep
+#                    working with bdwidth removed from the config
 #   usb_ok         - False while the USB connection is down (port: usb)
 #   usb_errors     - USB read errors since Klipper start
 #
@@ -54,7 +57,10 @@ class BDWidthStatus:
                                             self._handle_connect)
 
     def _handle_connect(self):
-        self.sensor = self.printer.lookup_object(self.sensor_name)
+        self.sensor = self.printer.lookup_object(self.sensor_name, None)
+        if self.sensor is None:
+            logging.info("bdwidth_status: no [%s] configured", self.sensor_name)
+            return
         if (getattr(self.sensor, 'port', None) == 'usb'
                 and callable(getattr(self.sensor, 'Read_bdwidth', None))
                 and getattr(self.sensor, 'usb', None) is not None):
@@ -96,6 +102,11 @@ class BDWidthStatus:
 
     def get_status(self, eventtime):
         s = self.sensor
+        if s is None:
+            return {'name': self.name, 'present': False, 'reading': False,
+                    'enabled': False, 'total_move': 0, 'last_motion': 0,
+                    'diameter': 0., 'active': 'disable', 'linear_motion': 42.8,
+                    'sample_time': 1., 'usb_ok': True, 'usb_errors': 0}
         # bdwidth's own get_status() is the runout helper's, which carries
         # the SET_FILAMENT_SENSOR enable flag
         try:
@@ -110,6 +121,7 @@ class BDWidthStatus:
                    and 'disable' not in str(getattr(s, 'is_active', 'disable')))
         return {
             'name': self.name,
+            'present': True,
             'reading': reading,
             'enabled': enabled,
             'total_move': getattr(s, 'actual_total_move', 0),

macros/afc/purge_check.cfg

@@ -65,13 +65,14 @@ gcode:
     # pause the printer (the check reports it instead). Afterwards the
     # runout response is restored; bdwidth itself is only switched off
     # again outside a print, so a print never loses it.
-    {% set bdw_on = cfg.motion_check and not printer.bdwidth_status.reading|default(false) %}
+    {% set has_bdw = printer.bdwidth_status.present|default(true) %}
+    {% set bdw_on = has_bdw and cfg.motion_check and not printer.bdwidth_status.reading|default(false) %}
     {% set bdw_off = bdw_on and printer.print_stats.state not in ["printing", "paused"] %}
     {% set runout_was = 1 if printer.bdwidth_status.enabled else 0 %}
     # Without the motion check, bdwidth's own runout response is off during
     # the purge too, so a bdwidth that does not see the movement cannot
     # pause the printer here; the pressure check judges the purge.
-    {% set runout_off = bdw_on or not cfg.motion_check %}
+    {% set runout_off = has_bdw and (bdw_on or not cfg.motion_check) %}
     {% if cfg.mode == "off" %}
         BLOBIFIER {rawparams}
     {% else %}

macros/afc/purge_until_empty.cfg

@@ -73,7 +73,7 @@ gcode:
         RESPOND MSG="PURGE_UNTIL_EMPTY: unsyncing {printer.AFC.current_load} from the extruder (UNSET_LANE_LOADED)"
         UNSET_LANE_LOADED
     {% endif %}
-    {% set bdw = printer.bdwidth_status.name if 'bdwidth_status' in printer else '' %}
+    {% set bdw = printer.bdwidth_status.name if 'bdwidth_status' in printer and printer.bdwidth_status.present|default(true) else '' %}
     {% set runout_was = 1 if bdw and printer.bdwidth_status.enabled else 0 %}
     {% if runout_was %}
         RESPOND MSG="PURGE_UNTIL_EMPTY: bdwidth runout response off during the purges"

macros/print/print_start_end.cfg

@@ -203,10 +203,9 @@ gcode:
 
     _AFC_STORE_HOME_REFERENCE
 
-    # Width only (flow compensation and runout when no filament is measured).
-    # The CCD motion reading stays at 0 (actual_total_move:0), so motion mode
-    # (ENABLE_MOTION / ENABLE_ALL) only gives false "Rounout" messages.
-    SET_BDWIDTH NAME=fila_width_0 COMMAND=ENABLE_WIDTH
+    # bdwidth is not used while printing: its motion reading stays at 0 and its
+    # per-reading width compensation made the flow jump between 77 and 119%.
+    # To use it again: SET_BDWIDTH NAME=fila_width_0 COMMAND=ENABLE_WIDTH
     
     _status_printing
 
@@ -252,7 +251,9 @@ gcode:
     TURN_OFF_HEATERS
     iHEATER_OFF                                     ; stops the chamber heater control loop too
     M107
+    {% if 'bdwidth fila_width_0' in printer %}
     SET_BDWIDTH NAME=fila_width_0 COMMAND=DISABLE   ; also sets M221 S100
+    {% endif %}
     M221 S100
     BED_MESH_CLEAR
     SET_SKEW CLEAR=1