Printing from SD Card - Temp set to zero after G28

Marlin Firmware Service Bug Reports
#1

Hi,
I changed FW
from Ender-3_4.2.7_Marlin2.0.1 - V1.1.2 - BLTouch - TMC2225.bin
to Ender3-v4.2.7-BLTouch-20211122.bin

When printing g-code file from SD card after command G28 extruder & bed temperature is set to zero.
Printing the same file via Pronterface / USB it works as expected. Temperature is kept unchanged.

Is it possible, that here is a SW bug or is the problem on my side?

Thanks
Tim

#2

I’d be suspecting problems with the start gcode.

There’s a few examples of start gcode in the FAQ posts.

#3

Hi,
thanks for the hint.
But I couldn’t see any curios in this code:
M140 S80
M104 S225
M105
M109 S225
M190 S80
M82 ;absolute extrusion mode
; Ender 3 Custom Start G-code
G92 E0 ; Reset Extruder
G28 ; Home all axes
G29 L15 R190 F20 B200 V4

When executing G28 temperature (nozzle and bed) is set to zero.
But only when printig from SD card.

With the older version it works.

#4

I have the same problem

#5

I’ve had a little bit of time to think about this - what may well be happening is that the nozzle specifically may be ‘timing out’. There is a timeout that stops your hotend from burning up the filament when there are no moves performed - however a G28 should easily complete within that timeout.

A slow moving G29 however may well trigger this timeout.

Normally, I’d recommend doing a G29 before you start printing, and then save the mesh to the EEPROM either via the screens menu, or the M500 command. You could then remove G29 from your start G-Code (if present) and have a more optimised flow…