# \[Marlin] M003 - Laser On

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**📅Update: 2020/09/18**
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## Description

Wait for moves to complete, then set the spindle speed (clockwise) or laser power.

## Notes

* 'S is interpeted as the configured value range: PWM (default), Percentage, or RPM. (See `CUTTER_POWER_UNIT`)'
* "[`M3`](https://app.gitbook.com/docs/gcode/M003.html) and [`M4`](https://app.gitbook.com/docs/gcode/M004.html) aren't needed with `LASER_POWER_INLINE` and `LASER_MOVE_POWER` enabled. Power is set directly in [`G1`](https://app.gitbook.com/docs/gcode/G000-G001.html)…[`G5`](https://app.gitbook.com/docs/gcode/G005.html)"

## Usage

`M3` `[I<mode>]`

### Parameters

* `[I<mode>]` Inline mode ON / OFF.

## Examples

Set spindle rotation clockwise at 50% with `CUTTER_POWER_UNIT` set to `PERCENT`

```
M3 S50
```

Set spindle rotation clockwise at 6K RPM with `CUTTER_POWER_UNIT` set to `RPM`

```
M3 S5000
```

Set laser power to 50% in PWM

```
M3 O128
```

Turn on the laser at full / `SPEED_POWER_STARTUP` power

```
M3
```

Fire laser at 80% on next G1,G2 and G3 move

```
M3 S204 I
```


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