PWM control 4 pin fan on Duet 3 6HC?

[Nxt-1]

I upgrading my delta from a Duet 2 wifi to a 3 6HC and am now wiring fans. Amoung which a standard 4 pin fan. The wiki says it's plug and play on out4-6.

M950 F2 C"!0.out4+0.out4.tach" Q25000
M106 P2 L0.0 X1.0 H-1 C"Duet"

I don't know if I have something configured wrong but it seems like the Duet is still just switching GND instead of applying a pwm signal to the proper pwm pin of the fan. Which result in the fan running either 100% or not at all (it does not suport voltage pwm mode).

[dc42]

@nxt-1 change it to:

M950 F2 C"!0.out4+out4.tach" Q25000

If you have wired it correctly then the PWM input of the fan goes to the negative switched output of the Duet.

[Nxt-1]

@dc42 The only think that changed is the ommited 0 from the out4.tach pin right? Either way I changed it and see no difference. In terms of wiring, it's a stock 4 pin 140mm Noctua fan so it follows the gnd/+12/tach/pwm pin standard.

[dc42]

@nxt-1 yes, that's the change. Without that change, I suspect the whole command would be rejected.

Have you tried either running the M950 command form the console, or alternatively running M98 P"config.g" to check whether the command is accepted?

[Nxt-1]

@dc42 I can run the command from console without issue wheter the extra 0 is there or not (I'd expect it to not be an issue as I understand it just refers to the mainboard explicitly instead of the default asume). Loading config.g from console also gives no issue.

Should it be helpful, I get a correct tacho signal reported by DWC.