---
tag: m0405
title: Filament Width Sensor On
brief: Enable filament width sensor flow control
author: thinkyhead

requires: FILAMENT_WIDTH_SENSOR
group: control

codes: [ M405 ]

notes: Requires `FILAMENT_WIDTH_SENSOR`.

parameters:
  -
    tag: D
    optional: true
    description: Distance from measurement point to hot end. If not given, the previous value will be used. The default startup value is set by `MEASUREMENT_DELAY_CM`.
    values:
      -
        unit: cm
        type: int

example:
  -
    pre: Start measuring filament width, adjusting flow
    code: M405

---

Turn on the filament width sensor and start using it to do flow control. Initially, the filament between the sensor and the hot-end will be treated as the nominal width.