16. Fan PWM to speed mapping
This section describes the mapping between fan PWM and expected speed in RPM. The IPU-Machine has five fan modules, named “fan0” to “fan4”. Each fan module consists of two fan rotors, one high speed fan rotor, and one lower speed fan rotor. The high speed fan rotor are named with even numbers, such as “fan0_0”, while the low speed fan rotor are named with odd numbers. Note that the fans are mechanical devices that will have slightly different mechanical characteristics that leads to some deviation in expected fan speed. The maximum allowed mechanically deviation is shown in the table below. The software will allow a maximum deviation of 20 %.
Fan type |
PWM [%] |
Expected speed [RPM] |
Mechanically allowed deviation [%] |
|---|---|---|---|
High speed |
40 |
9150 |
+-5 |
Low speed |
40 |
7990 |
+-5 |
High speed |
50 |
12193 |
+-5 |
Low speed |
50 |
10576 |
+-5 |
High speed |
60 |
15616 |
+-5 |
Low speed |
60 |
13512 |
+-5 |
High speed |
70 |
18934 |
+-5 |
Low speed |
70 |
16433 |
+-5 |
High speed |
80 |
21658 |
+-5 |
Low speed |
80 |
18906 |
+-5 |
High speed |
90 |
25264 |
+-5 |
Low speed |
90 |
22179 |
+-5 |
High speed |
100 |
28516 |
+-5 |
Low speed |
100 |
24813 |
+-5 |