PMW fan inversed output

x_pedro_x

I'm having an issue with the pwm fan setup in a duet 3 - 6hc, when using a 2 wire fan it works as expected but recently I decided to upgrade to pwm fans from noctua. When connecting them the fan will be running at 100% when the pwm in the interface is set to 0% and it will be off when the fan is set to 100% in the web interface.
The intermediate speed will also be decreasing as we increase the fan values in the web frontend.

I'm using the following sw version:

ii  duetcontrolserver                 3.2.2                               armhf        Control server application for Duet 3 series
ii  duetruntime                       3.2.2                               armhf        .NET Core runtime libraries for the Duet software framework
ii  duetsd                            1.1.0                               all          Virtual SD card directory for the Duet software framework
ii  duetsoftwareframework             3.2.2                               armhf        Meta package for the full Duet software framework
ii  duettools                         3.2.2                               armhf        Optional tools (code examples)
ii  duetwebcontrol                    3.2.2                               all          Official web interface for Duet electronics
ii  duetwebserver                     3.2.2                               armhf        Optional web server for Duet 3 series

And the following configuration for the fan:

M950 F1 C"out4" Q500                               ; create fan 1 on pin out4
M106 P1 C"Layer fan" S0 H-1 -L255                  ; set fan 1 value. Thermostatic control is turned off

Does someone have an ideia of what it could be, I suspect the L parameter on M106 but would like to confirm it.

Cheers,
Pedro

dc42

@x_pedro_x said in PMW fan inversed output:

M950 F1 C"out4" Q500 ; create fan 1 on pin out4

Use this instead for 4-wire fans:

M950 F1 C"!out4+out4.tach" Q25000

The ! inverts the output, the +out4.tach enables the tacho input so that you can read the fan RPM, and Q25000 sets the PWM frequency to 25kHz which is the recommended value for 4-wire fans.

x_pedro_x

@dc42 Awsome, it worked like a charm! Thanks for the quick answer on a weekend.