<p>You are correct about needing to specify the dwell value in milliseconds. However, the RepRap Wiki indicates that you need to use the <code>Pn</code> argument, and not just an unadorned number as the argument to the command. To adapt the Wiki's own example, you will need to use:</p>

<pre><code>G4 P30000
</code></pre>

<p>This should cause the firmware to dwell (pause) for 30 seconds.</p>

<p><a href="http://reprap.org/wiki/G-code#G4:_Dwell" rel="nofollow noreferrer">RepRap Wiki: G4: Dwell</a></p>

CC BY-SA 3.0
2017-10-29T01:33:32.047Z
2017-10-29T01:33:32.047Z
Mick
<p>Depending on your G-code flavor you may be able to use <a href="https://reprap.org/wiki/G-code#M109:_Set_Extruder_Temperature_and_Wait" rel="nofollow noreferrer"><code>M109</code></a> (heat and wait) instead. If supported M109 will wait until the target temperature is achieved.</p>

CC BY-SA 4.0
2019-05-23T04:20:21.007Z
2019-05-23T13:47:52.490Z
2019-05-23T13:47:52.490Z
Larry
<p>I am writing some G-code for my DIY 3D printer. From what I understand, <code>G4</code> is dwell and its expressed in milliseconds. So my extruder takes about 30 seconds to heat up. Do I just type </p>

<pre><code>G04 30000
</code></pre>

CC BY-SA 4.0
2019-05-23T07:31:54.677Z
This question suffers from the [XY problem](https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem). Mick's answer accurately addresses the titular question, while Larry's actually gives the best solution for your problem? Is there any reason you need to do the waiting based on a fixed period of time (e.g., because your extruder does not have closed-loop temperature feedback)?
Tom van der Zanden
<g-code>
How to express dwell time in G-code
Keith Bybee
# How to express dwell time in G-code

(Asked by: username_0 on 2017-10-29)

I am writing some G-code for my DIY 3D printer. From what I understand, G4 is dwell and its expressed in milliseconds. So my extruder takes about 30 seconds to heat up. Do I just type 
G04 30000

**Tags:** g-code
> **Comments:**
> **username_1**: This question suffers from the [XY problem](https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem). Mick's answer accurately addresses the titular question, while Larry's actually gives the best solution for your problem? Is there any reason you need to do the waiting based on a fixed period of time (e.g., because your extruder does not have closed-loop temperature feedback)?  

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## 2 answers

### Answer by username_2 on 2017-10-29. Score: 2 | Accepted answer

You are correct about needing to specify the dwell value in milliseconds. However, the RepRap Wiki indicates that you need to use the Pn argument, and not just an unadorned number as the argument to the command. To adapt the Wiki's own example, you will need to use:
G4 P30000

This should cause the firmware to dwell (pause) for 30 seconds.
RepRap Wiki: G4: Dwell


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### Answer by username_3 on 2019-05-23. Score: 4

Depending on your G-code flavor you may be able to use [`M109`](https://reprap.org/wiki/G-code#M109:_Set_Extruder_Temperature_and_Wait) (heat and wait) instead. If supported M109 will wait until the target temperature is achieved.


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