ABB FDNA-01 - Speed Actual (AC;DC Drive Object)

86 Communication profiles
Speed Actual (AC/DC drive object)
This attribute indicates the actual speed at which the drive is
operating. The units are scaled by the SpeedScale attribute of the
AC/DC drive object. See Table 4. for details.
Scalar mode
When the drive is operating in the scalar mode, the drive provides
the adapter module with a frequency actual. The ODVA AC/DC
drive profile uses rpm units for the speed actual. The ODVA Speed
Actual is calculated as follows:
where
For example, for a 4 pole 60 Hz motor (Mss = 1800 rpm) with a unit
of 1 rpm and a Drive frequency actual of 30 Hz, the ODVA Speed
Actual is:
Osa = ODVA Speed Actual
Dfa = Drive frequency actual in Hz
Us = ODVA speed unit (see 10 ODVA SPEED SCALE on page 41)
Mf = Motor nominal frequency in Hz
Mss = Motor synchronous speed in rpm (not motor nominal speed)
UsM
f
Mss Dfa
Osa
×
×
=
900
1rpm60Hz
1800rpm30Hz
UsMf
MssDfa
Osa =
×
×
=
×
×
=