Modes:

Manual:
	Buttons to inc/dec fan speed(0-10V) (show in percents 10% == 1V)
	Display fan speed + pressure.
	Fan updates at the same time as UI
Automatic:
	Buttons to inc/dec fan pressure level (0-120 Pa) (show in percents 10% == 1V)
	Pressure to inc/dec fan speed

BTN1: auto/manual
auto: BTN3 - inc pressure,  BTN2 - dec pressure
manual: BTN3 - inc voltage,  BTN2 - dec voltage
