![ABB Relion 620 Series Technical Manual Download Page 951](http://html.mh-extra.com/html/abb/relion-620-series/relion-620-series_technical-manual_2838045951.webp)
Technical revision
Change
D
Internal improvement
E
Internal improvement
8.1.9
Frequency measurement FMMXU
8.1.9.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Frequency measurement
FMMXU
f
f
8.1.9.2
Function block
Figure 506: Function block
8.1.9.3
Functionality
The frequency measurement range is 35...75 Hz. The estimated frequencies outside
the measurement range are considered to be out of range and the minimum and
maximum values are then shown.
When the frequencies cannot be measured, for example, due to too low voltage
amplitude, the default value for frequency measurement can be selected with the
Def frequency Sel setting parameter. In the “Nominal” mode the frequency is set
to 50 Hz (or 60 Hz) and in “Zero” mode the frequency is set to zero and shown in
parentheses.
8.1.9.4
Signals
Table 926: FMMXU Input signals
Name
Type
Default
Description
F
SIGNAL
–
Measured system frequency
8.1.9.5
Settings
1MRS757644 H
Measurement functions
620 series
Technical Manual
951