4-wire PWM fan standard dictates the PWM driver have an open-collector output, which means it has to be pulled low for the fan to see "low" and floating means "high". Standard also states I believe 24KHz with about 4KHz of play to either side as within tolerance.
I've got an idea for a controller that wouldn't take more than about a day to put together, but it could be set to either a maximum or minimum PWM. It'd detect the controller's drive PWM and override it if it crossed threshold. Something like that would be useful for an undervolted miner or S7LN where when the miner first kicks on the fan pulls up to 100% and it's loud. Or it could give a lower threshold to limit the up-and-down throttling of the autotune miners.
Probably should have had something like this prototyped already. I figured out how to do the PWM detect and override like a month ago, just haven't gotten around to coding it.
I've got an idea for a controller that wouldn't take more than about a day to put together, but it could be set to either a maximum or minimum PWM. It'd detect the controller's drive PWM and override it if it crossed threshold. Something like that would be useful for an undervolted miner or S7LN where when the miner first kicks on the fan pulls up to 100% and it's loud. Or it could give a lower threshold to limit the up-and-down throttling of the autotune miners.
Probably should have had something like this prototyped already. I figured out how to do the PWM detect and override like a month ago, just haven't gotten around to coding it.
I was just thinking of this as well.
A controller that monitors the low, and won't allow it to drop bellow a set value, possibly also can do the same for the high? would be nice to keep the fans just under that nice whistle, around 3700RPM, above that they seem to whistle.
I'd buy this, please if you do it let me know, I'll be the first in line!
