Fan on RouterBoard 333

Hardware MikroTik hardware general
1

Situation:
I have 12V fan with rotation feedback (Sunnon KDE1204PFV1) connected to RB333. Fan is connected to outer connector (closer to the PCB border). Connector is described as “FAN1” on PCB. Fan runs. ROS is reporting it as:
[admin@RB333] /system health> pri
fan-mode: auto
use-fan: main
active-fan: auxiliary
voltage: 13.9
Connector marked FAN1 seems to be “auxiliary” in ROS.
When I set fan-mode=manual fan stopped.

If the fan is connected to next connector (closer to mini-pci), setting fan-mode seems not have any effect.

Question is: why?
What does it mean fan-mode=auto and use-fan=main?
These parameters is not described in documentation …

2

OK. I tried to connect two same fans. I think ROS controls them to keep active only one.
If fan-mode=auto is set, main fan (FAN2 on PCB) is activated. Auxiliary fan stays inactive until main fan is stopped (disconnected or stopped physically). If auxiliary fan is started, main fan stays stopped till auxiliary fan runs.

If fan-mode=manual is set, runs only the fan specified in use-fan=….

I regret that ROS knows from rotation feedback sensor whether fan rotates, but does not supply information about its RPM :frowning: .