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

group: control
requires: FILAMENT_WIDTH_SENSOR

codes: [ M405 ]
related: [ M404, M406, M407 ]

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.
