Buck converter , switch off pwm ?

peter247

Hi , I want to control a 12volt fan using a 24v to 12v buck converter .
Just want to switch it on or off not control the speed with pwm , on version 3.1.1 can I switch the pwm off are is that by setting the maximum setting 255 ?.

Phaedrux

Switching it on and off is the same as controlling the speed.

M106 S0/S1 would be off and on.

The switching is done on the negative side. Your buck converter can either power the entire fan bank by connecting positive to the v_fan jumper, or you can power just that one fan by connecting the buck converter positive to the fan positive and the fan negative to the fan port negative. Then control the fan with M106.

https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans#Section_Using_12V_fans_when_VIN_is_24V

peter247

@Phaedrux

So if you don't set the Q do you get a binary on or off ?

M950 F2 C"fan2" Q500

Phaedrux

The on and off is always going to be PWM based, the frequency is irrelevant for the off state and for the on state you're going to want to use one that works well for the fan. Q500 is the default.