Tool fan temp control again

  • Hi *,

    I have again a problem with my fan which should cool the hotend. This time with the 3HC. (I build a new printer)

    The fan (F1) spins all the time but I want to have it started at 45°C. That is the case when the fan is connected to "1.out3" including the tacho signal. So I connected it to "1.out5" (without the tacho) and it was working there.
    What do I do wrong here?

    The current config:

    ;; Heaters
    ; Bed         ##################### TODO
    M308 S0 P"temp0" Y"thermistor" T100000 B4138 ; configure sensor 0 as thermistor on pin temp0
    M950 H0 C"out0" T0                           ; create bed heater output on 1.out0 and map it to sensor 0
    M307 H0 B0 S1.00                             ; disable bang-bang mode for the bed heater and set PWM limit
    M140 H0                                      ; map heated bed to heater 0
    M143 H0 S120                                 ; set temperature limit for heater 0 to 120C
    ; Hotend
    M308 S1 P"1.temp0" Y"thermistor" T500000 B4723 C1.196220e-7  ; configure sensor 1 
    M950 H1 C"1.out0" T1                         ; create nozzle heater output on 1.out0 and map it to sensor 1
    M307 H1 B0 S1.00                             ; disable bang-bang mode for heater  and set PWM limit
    ;; Fans         ##################### TODO
    ; Fan for the printed part:
    M950 F0 C"1.out6" Q500                       ; create fan 0 on pin 1.out4 and set its frequency
    M106 P0 S0 H-1                               ; set fan 0 value. Thermostatic control is turned off
    ; Fan for the Hotend:
    ;M950 F1 C"1.out5" Q500                       ; create fan 1 on pin 1.out5 and set its frequency
    M950 F1 C"1.out3" Q500                       ; create fan 1 on pin 1.out5 and set its frequency
    M106 P1 S1 H1 T45 ; C"Hotend"                  ; P="set fan 1" S="value" H="Thermostatic control Heater No." T=" is turned on at 45°C"
    ; Tools         ##################### TODO
    M563 P0 S"TooL0" D0 H1		                 ; define tool 0
    G10 P0 X0 Y0 Z0                              ; set tool 0 axis offsets

    Cheers, Chriss

  • Moderator

    Firmware version? Is this with a 4 wire tach fan?

  • @Phaedrux
    FW 3.1.1
    It is a three wire Fan. It makes no difference whether I connect the third wire or not.

  • Moderator

    Then it is not a PWM tacho fan. The third wire is likely just an RPM sensor and can be ignored. The duet PWM control is done through switching of the negative leg.

  • @Phaedrux
    Fair enough, but whats the reason than that it is aways on at 1.out3? I can connet the fan to 1.out5 but I would like to understand the behaviour.

  • M106 P1 C"Hotend" S1 H1:0 T45

  • Moderator

  • @Phaedrux

    Honestly, I wired it to "1.out3", "1.out5 " and "1.out7"

    My conclusion is now:

    It works with the fan wired to "1.out7" and this config:

    M950 F1 C"1.out7" Q500                       
    M106 P1 S1 H1 T45 ;C"Hotend"

    (With or without the 'C"Hotend", here off for reference')

    And the fan is always on when I wire it to "1.out3" and configure like that:

    M950 F1 C"1.out3" Q500                       ; create fan 1 on pin 1.out5 and set its frequency
    M106 P1 S1 H1 T45 ;C"Hotend"

    (With or without the 'C"Hotend", here off for reference')

    I connected only "plus" and "ground" to the connectors.

    And it seems that I'm not fully wrong here because it works as expected on "1.out7". :?

    I'm close to giving up here. At the end will it not make a difference whether it is connected to "1.out3" or "1.out7" when the rpm signal is useless here.

    (Yes, I mixed up some ports in my posting yesterday and I apologize for that.)

    Cheers, Chriss

  • @Chriss So it is out7 that works, not out5 as you previously stated yes? That makes a difference. There are separate voltage jumpers for out 3 to 5, and out 6 to 8. Is there a jumper fitted to the out3 to 5 select pins and if so, is it set the same as the jumper for out 6 to 8? One reason the fan might not work on out 3 to 5 is that it's a 24V fan but the jumper is set to 12V or that the jumper is missing.

  • @deckingman

    I do not think that I have a voltage problem here. The Fan is spinning all the time, the temperature control do not work on. In other words: It seams like "T45" has no effect on at "1.out3" but on "1.out7".
    So it does not seams like a conif problem, more like a understanding problem. My best guess is that the rpm fan connectors can not be controlled by "T".

    Cheers, Chriss

  • @Chriss Hmmm. I guess that's a possibility. I have to confess that all my fans are 2 wire so I found it more convenient to use the 2 wire out connectors. Hopefully a moderator or DC42 will step in and confirm what you think is true or otherwise.

  • @deckingman

    I hope for a confirmation, too. It would be good to know for education. 😉

    I will connect the fan to 1.fan7 and that's it than.

    Cheers, Chriss

  • @dc42

    Can you enlighten us here, please? 😉

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