4 Wire PWM 12v Fan on 2 wire PWM Connection (DUET3 Mini5)

[JabawokJayUK]

Hi, I have run out of 4 wire connectors on my latest design and need to pwm control a 4 wire fan. According to the documentation OUT_5 & OUT_6 are PWM Fan connectors but they are only 2 wire.

My question is, how should I wire it?

I was thinking to take +12 & -12v to the main 12v supply, and then have the blue PWM control wire go to the out5- and disconnect tach so I have PWM control from the DUET?

Any thoughts on this one?

Many thanks!

[jay_s_uk]

@JabawokJayUK out3 and out4 can control 4 wire fans

[JabawokJayUK]

@jay_s_uk Thanks, yes, they are currently doing that. I need more pwm outputs if that was not clear in my initial problem declaration.

[jay_s_uk]

@JabawokJayUK in that case what you're proposing should work.
or just use the + and - and control them as a 2 wire fan

[dc42]

@JabawokJayUK said in 4 Wire PWM 12v Fan on 2 wire PWM Connection (DUET3 Mini5):

I was thinking to take +12 & -12v to the main 12v supply, and then have the blue PWM control wire go to the out5- and disconnect tach so I have PWM control from the DUET?

That should work. If you have a spare IOx.IN port then you could try using that for the tach.

[JabawokJayUK]

@dc42 interesting. io5&6 are currently unused. So potentially, the idea would be to use "!out6+io6.in" to maintain the tach signal and pwm control with offloaded power.

I profess to having a spare Toolboard 1LC so I am currently redrawing my diagram to move the cab control, which this fan is a part of, to it entirely, mitigating the problem. I was just interested to see if I could get it all on the mini5, all be it with both temp & stepper daughter boards installed for extra connectivity!