M140 not working, gcode cannot adjust bed temp mid print

Using latest firmwares 1.12.0
I am using PrusaSlicer, and have noticed that the ‘other layers’ bed temp isnt being set.

I have 70 for first layer, but want 50 for the rest. This works when slicing with luban, but not with PrusaSlicer (I have to wait for the first layer to end then adjust bed temp on the touchscreen). See attached gcodes.

luban_xyzCalibrationcube_58548000.gcode (316.8 KB) prusaslicer_xyzCalibration_cube.gcode (411.0 KB)

The touchscreen logs contain lines like:
DEBUG,SC,Override M140 S70.0
Which make it sound like the touchscreen is overriding the gcode. Is this the case? Why?

I think (no proof, just experience with octoprint) if you have the touch screen open to the control panel, it’ll occasionally send gcode to the printer. I’ve found it’s best to make sure to completely back out of the control screen (e.g. go all the way back to the main screen) when starting a print (again, I use octoprint and start my prints from there).

FWIW, I’m using superslicer and setting temp changes at higher layers and it’s working fine for me (provided I don’t touch the touch screen).

I appreciate the insight, unfortunately my actions are to browse to the file with the File menu, select it, then start. Perform absolutely no other action, and the bed temp does not change.

@Edwin any ideas? I’ve also noticed the touchscreen occasionally just ignore my temp change inputs completely and fail to do anything until I set it to zero, then back to the temp I want

Let’s put a special circumstance.

Pause the machine → Modify the heated bed target temp on touchscreen from 50 degrees to 70 degrees → Resume the work

  • First, the touchscreen will record your action as following.

DEBUG,SC,Override M140 S70.0

  • Second, touchscreen will send the signal to Controller. And FW log will record the action as well.

  • Third, the target temp will update to the new value and you can see that on the touchscreen.

  • The machine will resume the work and approach to the new target bed temp simultaneously.

Hope this helps.


Well, this is odd.

After your suggestion I tried SuperSlicer and its working as expected.

Guess I’ll be using that now!
Would be very interested to know why the PrusaSlicer gcode doesnt work

Maybe try slicing the exact same in prusaslicer/superslicer, then diff the 2 files, and compare the gcode (might be better to just remove all the G1 lines), and see what super does different then prusa (they should be nearly identical though…)

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