Fan Speed Firmware Bug?

[mechamecha 63]

I've noticed that if I try to ramp up my fan speed very gradually over several millimeters (using "Fan full on at height" in Cura), the fans never actually turn on, even though the display shows the fan speed percentage increasing by a small percentage on each layer in the Tune menu. I have to manually play with the setting to get the fans jump started. Is this a firmware bug?

[gr5 1,346]

The fans need around 25% to 30% to get started.  Once moving you can lower to around 20%.  Maybe even lower.  There is a feature that if you go from *off* to 20% it over powers the fans at 100% for a half second or so then lowers to 20%.  This works great and jumpstarts them but if the first layer is 5% and the second layer is 10% it only jumps 0-5% and not 5-10% so the fans don't come on until around 30%.

by the way the % represents the duty cycle. So if the fan is at 50% that means it is at full power/voltage for half the time and off the other half the time. The cycle is 5 to 10 times per second. Same method for setting power to the heater in the nozzle.

Edited June 7, 2015 by Guest

[IRobertI 450]

It also differs between fans. Some come on earlier than others.

[mechamecha 63]

Ah, I get it now. Thanks!