11-20
IM WT3001E-51EN
11.10 FFT Function Specifications
Computation Function
Item
Specifications
Computed source
Voltage, current, active power, and reactive power of each input element.
Active power and reactive power of an Σ wiring unit.
Torque and speed signals (analog input) of motor input (option).
Type
PS (power spectrum)
Number of computations
Two computations (FFT1 and FFT2)
Maximum frequency of
analysis
100 kHz
Number of points
20,000 points or 200,000 points
Measurement period for
the computation
100 ms or 1 s
Frequency resolution
10 Hz or 1 Hz
Window function
Rectangular, Hanning, or Flattop
Anti-aliasing filter
Set using a line filter (OFF, 500 Hz, 5.5 kHz, or 50 kHz).
Measurement Function
Item
Specifications
Sampling clock
Fixed to 200 kHz
Display update
Data update interval or (measurement period of the FFT + FFT computing time), whichever is
longer
* The measurement period is 1 s when the number of FFT points is 200 k (when the frequency resolution is 1 Hz).
The measurement period is 100 ms when the number of FFT points is 20 k (when the frequency resolution is 10 Hz).
Functional Limitations
Item
Specifications
Display
Trend display, bar graph display, vector display, and waveform computation display are not allowed.
Harmonic measurement
Not allowed
Equation for apparent
power and reactive power
Type3 not selectable.
If FFT mode is enabled while Type3 is set, Type1 is automatically selected.
Integration
Not allowed
Trigger Mode
OFF not selectable.
If FFT mode is enabled while OFF is set, Auto is automatically selected.
Store
Not allowed
Synchronized measurement Not allowed
Auto print
Integration synchronization is not allowed.
Measurement Functions
Measurement is not allowed for measurement functions related to the functions above
that have limitations. For a list of measurement functions that cannot be measured, see
appendices 10 and 11 in the
User’s Manual IM WT3001E-01EN
.
