My new (to me) Foxsat is running a bit warm for my liking so I've been observing the fan behaviour to see what it does when left alone before I do something to fix it. Didn't find it documented anywhere so, for the record:
The Foxsat firmware triggers the fan based on the temperature of the hard disk drive, specifically attribute 194; the fan speed is controlled via pulse-width-modulation (PWM)*.
The system starts with the fan turned off and leaves it off until the temperature reaches 51 centigrade at which point it sets it to half speed (0x7fff) until it drops again to 46° at which point it turns off.
Looking at the code**, there are two other fan speeds used making the full set:
< 47°C - off
> 51°C - 0x7fff (50%)
> 62°C - 0xa491 (64%)
> 64°C - 0xc923 (78%)
* The PWM has 16-bit resolution (compared to 8-bit on the Freeview T2).
** I'm not getting my disk hot enough to verify by observation!
The Foxsat firmware triggers the fan based on the temperature of the hard disk drive, specifically attribute 194; the fan speed is controlled via pulse-width-modulation (PWM)*.
The system starts with the fan turned off and leaves it off until the temperature reaches 51 centigrade at which point it sets it to half speed (0x7fff) until it drops again to 46° at which point it turns off.
Looking at the code**, there are two other fan speeds used making the full set:
< 47°C - off
> 51°C - 0x7fff (50%)
> 62°C - 0xa491 (64%)
> 64°C - 0xc923 (78%)
* The PWM has 16-bit resolution (compared to 8-bit on the Freeview T2).
** I'm not getting my disk hot enough to verify by observation!