v3 firmware treats Fan 0 as "special"?



  • Hi,

    With the new boards and v3 firmware we have great flexibility to determine what does what.

    For example on my Mini 5 there are no outputs labeled as "fan" outputs so I am free to pick a output that best suits the need.

    But Fan 0 still plays a "special" roll with v3 M106 at least.

    From the M106 docs:

    If an S parameter is provided but no other parameter is present, then the speeds of the print cooling fans associated with the current tool will be set (see the F parameter in the M563 command). If no tool is active then the speed of Fan 0 will be set. Either way, the speed is remembered so that it can be recalled using the R2 parameter (see below).

    Perhaps in keeping with the new "anything can be anything" (within limits of course) perhaps the behavior above should be altered to allow specifying in some manner what fan should be used for M106 commands that don't specify a fan when no tool is active.

    Just a thought.

    Frederick


  • administrators

    In RRF3, Fan 0 is on whatever pin you assign it to in the M950 F0 command.



  • @dc42 said in v3 firmware treats Fan 0 as "special"?:

    In RRF3, Fan 0 is on whatever pin you assign it to in the M950 F0 command.

    Yes, that is understood.

    I started with this:

    M950 F0 C"out5" Q500
    M106 P0 C"Hotend" S255 H1 T40
    
    M950 F1 C"out6" Q500
    M106 P1 C"Part" S0 H-1
    

    and that worked fine for the most part because of this:

    M563 P0 S"T0" D0 H1 F1
    

    which mapped M106 Snnn commands to the "part" fan even though it was fan 1.

    What I failed to take into account is that M106 Snnn commands when no tool is active still controlled fan 0.

    With M565 we can map T0, T1, T2, etc to whatever fans we wish.

    What I feel is missing is, perhaps, a version of M565 that would allow fan mapping when no tool is active - something like M565 P-1 Fnnn - the P-1 syntax being consistent with the command T-1 for specifying no tool active.

    I see this as desirable as it allows fan assignments to not have to take into account the special case of M106 Snnn when no tool is active.


    It's not a big deal as I can re-assign that fans to be sure fan 0 is my part cooling fan but I still feel the idea is worth considering.

    Frederick


  • administrators

    @fcwilt said in v3 firmware treats Fan 0 as "special"?:

    It's not a big deal as I can re-assign that fans to be sure fan 0 is my part cooling fan...

    That is exactly what we advise in the documentation. https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans#Section_General_recommendations



  • @dc42 said in v3 firmware treats Fan 0 as "special"?:

    @fcwilt said in v3 firmware treats Fan 0 as "special"?:

    It's not a big deal as I can re-assign that fans to be sure fan 0 is my part cooling fan...

    That is exactly what we advise in the documentation. https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans#Section_General_recommendations

    That is also understood.

    And back when all the boards had outputs labeled "fan 0" and needed pin names "fan 0" it made a certain sense.

    But with the new boards with generic names for outputs and pins attaching a special significance to fan 0 seems odd to me, particularly with multiple tool setups.

    Would it be difficult to have something along the lines of M565 P-1 Fnnn?

    However that's just my two cents.

    Frederick


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