Most fan control software use a voltage % on the y axis and temperature on the x axis. I was trying to find fan control that uses the tachometer signal from the fan as an input rather than voltage %. The reason I ask is because a stationary fan needs a certain voltage to begin to spin however, once the fan is spinning that same voltage will spin the fan at a faster rpm than desired. If a target of 100 rpm could be imputed to a fan control that uses the tachometer signal then a stationary fan could be started with a higher voltage and then once the software saw the fan was over 100 rpm it would reduce the voltage to slow the fan back down to the 100 rpm target. ie, closed loop fan control. Any help would be appreciated.