3.4b2 - Unable to restore cooling fan speed?

[TechNi]

I've noticed that my printer does not restore the cooling fan speed after a toolchange despite being told to do so. Usually when a tool is freed, the PC fan is turned off and turned on again when the tool is selected.

So I created a little test script where I simply turn on & off the fan (no toolchange involved) and it indeed does not seem to work

T0 P0
M106 S1
G4 S1
M106 P0 S0
G4 S1
M106 P0 R2 ; This should turn the fan back on, no?

Can anyone test the script and post their firmware version in case it works or post an adjusted script where it works?

[dc42]

@techni that should only turn the fan back on if it was already turned on before the T0 command.

[TechNi]

@dc42

Thanks, I edited the script a little bit and now it works

T0 P0
M106 S1
T1 P0
G4 S1
M106 P0 S0
T0 P0
G4 S1
M106 R2 ; This should turn the fan back on, no?

Note that replacing the last line with "M106 P0 R2" does not work. This is probably the reason why my printer did not restore the fan speed after toolchange. Not sure if this is intentionally or not.

[dc42]

@techni said in 3.4b2 - Unable to restore cooling fan speed?:

Note that replacing the last line with "M106 P0 R2" does not work. This is probably the reason why my printer did not restore the fan speed after toolchange. Not sure if this is intentionally or not.

Yes, it's intentional. Most slicers don't know about M106 P parameters, so they generate M106 with no P parameter. RRF recognises this as a command to set the speed of the "current print cooling fan" and it remembers the last-selected speed requested in this way separately from speeds requested of numbered fans.