How to express dwell time in G-code 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
Depending on your G-code flavor you may be able to use M109 (heat and wait) instead. If supported M109 will wait until the target temperature is achieved.