Does an M104 with a tool select alsoswitch to that tool

  • Trying to understand dual extruder use with Duet and Cura - so maybe this is a Cura forum question...
    Anyway, my Kossel is setup with dual extruders and I have a test print being sliced in Cura 3.6 - the active extruder always seems to be at the wrong temperature or playing catch-up.
    Looking through the code, I am confused about where the tools are switched - Cura adds "T0" and "T1" at various points but I have the impression that the "M104 Sxxx T1" (or T0) also toggles the current tool.
    Duet is a ethernet version at 2.01 if that makes a difference.

    All thoughts welcomed!

  • administrators

    M104 doesn't change tool, but M109 does if no tool is selected.

  • Thanks David - so looking at the following snip:
    G92 E0
    M109 S220.1
    M104 T0 S195
    ;MESH:single box - Part 1(1).stl(1)
    G0 F3600 X-6.253 Y37.329 Z0.2
    G1 F1500 E-3

    I read as:
    switch to T1, read the (T1) temperature, set the default T0 to 220.1°C and wait, then dump T0 back to 195°C, then print using T0.....

    which I guess is a Cura problem

  • administrators

    The M109 command doesn't specify a tool and T1 is already selected. Therefore, if tool 1 exists, the M109 command won't cause a tool change.

  • Ok, I think I understand now - my start code turns both heaters on as well as the bed and waits until they get to temperature. I then squirt a bit from each nozzle prior to the 'real' code starting. However....because the last selected tool is #1 after the initial squirt and because Cura doesn't specify directly to start using T0 at this point, everything gets out of sync until the first specified toolchange.
    Hey ho, these dual setups are not trivial!
    Thanks again for your input


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