Mesh leveling data is drawing over the printing screen #1009
Description
Bug Description
When a new auto mesh leveling is required prior printing, the G29 (or G29 P1 for UBL) code needs to be inserted in the G-code start script but it may result in this:
This is caused by an incorrect position of the G-codes that heat the bed and the hot-end. By example, this G-code snippet will cause that error:
...
G28;
G29;
M190 S{first_layer_bed_temperature[0]};
M109 S{first_layer_temperature[0]};
M104 S170 ;
...Temperature has high priority in the firmware, and changing temperatures in the middle of printing process will trigger the printing screen. So due to the priority, it will run the M190 without waiting for mesh leveling to complete, then, the mesh points will be drawing over the printing screen.
The correct way of set the start G-code script is detailed in: https://github.com/mriscoc/Ender3V2S1/wiki/Slicer-G-code-Scripts
...
M104 S[first_layer_temperature] ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S[first_layer_temperature] ; wait for extruder temp
G28 ; home all
G29 ; Run mesh leveling on every print (or G29 P1 for UBL)
M500; Save mesh data (or G29 S0 for UBL), optional
C108 ; Close the mesh viewer, optional
...