m303M249, M303, M337, MT365, M373, MS327, MST326, M343, M346, M347) Post, or Electronic (eTMA) PDF All postgraduate mathematics modules, except M840 (M820, M821, M823,M303 is a G-code command that auto-tunes the PID system for the hotend or the heated bed of a 3D printer. It takes parameters such as cycles, hotend index, target temperature and