Using awesome miner firmware, I have a target temperature set of 77 C. My fan runs very quiet, temps creep up to 77, then fans kick on full blast for 3 seconds. Temps go back to 72, and quiet again. Repeat every couple minutes. It's very annoying because I usually have my L3+ running in my house. Can you fix the logic to work like Blissz silent profile (fan will slowly increase speed until stable at target temperature). And then don't decrease speed until there's a delta of 2-3 degrees AND 1 hr has elapsed since last increase (to avoid constant changes in fan speed). The key is reducing changes in fan speed as this increases perceptible noise (your brain drowns out white noise perfectly unless it's constantly changing).
Right now the strategy of jumping to 72-77 deg with fan going from 900 rpm to full blast is very bad for electronics in terms of thermal cycling, and bad for airflow since I have multiple antminers connected to same exhaust area (so if one is randomly going to full blast it will backflow to others that are barely at speed). Need them all nice and stable!
Edit:
Did more testing
It appears that no matter what you set your target temperature to, when it hits 77 C, max fan speeds apply and temporarily override everything for 10 sec.
Set target to 80 C, it will only get to 77 before applying max fans, dropping temp back to 72
Set target to 77 C, it will still get to 77 and apply max fans
Set target to 76, it will be ok at first with gentle fan increases, but then barely jump into 77 ...and jump to full blast
Set target to 75, it will be ok most of the time...gentle fan increases to 75-76, and more rarely bump to 77 and then go full blast still.
Set target to 74, it will sometimes overshoot to 75-76, but small fan increases will stop it from hitting 77, so we're always nice and quiet. Adjustments are still +/-200rpm which is noisy and over shoots the low end.
Set target to 70, it makes very quiet, minor fan adjustments (+/- 20rpm), I like this! Perfect behavior. But I wish I could have my system stay warmer (76 C range) with this small adjustment behavior because I prefer slower 76 C fan load compared to to 70 C fan load.
So I think I found the fix: Undo the 77 C hard coded max fan speed. Since the default target is 65, adding 12 to 65 = 77. If I change target temperature, change max fan speed override to (target)+12. So if I set a target of 75, don't start overriding fast fan speeds until it approaches 87.
Hope that makes sense!
Also if fan check is on, the antminer will restart when hitting 77, and the tuning page says "Fan Err! Disable PIC! Fan1 speed is too low 1770 pwm 100". If I disable fan check, the error goes away and no restart happens. Very weird since this shows up when fans go faster.
Can you please let me know the configured temperature for "Chain disable temp" (the overheat feature)? Please also try to increase this value.
The firmware will try to make sure you are at least 10 C below this temperature and can increase the fan speed if needed. By increasing this temperature limit it will be less likely you run into a high fan speed.