Just connected a cooling fan to my M90 and have it hooked to D9 on my ramps board. M106 S### only turns on the fan if ###>=128 and any value from 128-255 just turns it on full speed. I'd like to get full variable speed control not just binary on/off. I do have the red wire of the fan connected to the + terminal of the ramps board as well.
Wondering if maybe anyone had any insight or bits of knowledge they could drop on me.
