User Manual – Rev AJ California Instruments
4.5.3 Accuracy Considerations
Any measurement system has a finite accuracy specification. Measurement specifications are
listed in Section 2. When using the AC source for measurement purposes, always consider
these specifications when interpreting results. Measurement inaccuracies become more
pronounced as the signal being measured is at the low end of the measurement range. This is
particularly relevant for low current measurements. The MX Series is a high power AC and DC
source optimized for providing and measuring high load currents. When powering low powe
loads, mea
r
surement inaccuracies on rms and peak current measurements will greatly affect
derived measurements such as power, power factor and crest factor.
t system on the MX Series I uses a data acquisition system with a 6.6 kHz
at high frequency
When using an external measur
readings.
4.6 Advanced Measurements
The measuremen
bandwidth in three-phase mode. The MX Series uses 16 kHz. This means th
components of the measured signal are filtered out. Any contribution to the rms value of voltage
and current above this cutoff frequency will not be reflected in the MX Series measurements.
ement reference, this may account for discrepancies in
[3Pi Controller only]
The 3Pi controller offers advanced power analyzer measurement capabilities. These functions
may be accessed from the MEAS button or the MENU 2 screen. The phase for which the
configurations. This chapter cov
functions.
4.6.1 Harmonic Analysis
analysis or waveform acquisition is done may be selected using the PHASE key in three phase
ers the use and application of these advanced measurement
The 3Pi controller’s power analy
and current on each available ph ectrum can be displayed on the
LCD display in a tabular as well as a graphical mode.
4.6.1.1
zer performs fast Fourier transformation (FFT) on both voltage
ase. The resulting frequency sp
Acquiring FFT data
To perform an FFT analysis on the output of the AC source, proceed as follows:
1. Press the MEAS button four times or until the HARMONICS/TRACE ANALYSIS screen
appears.
CTION field and select VOLT or CURR. (The BOTH selec
one FFT result can be displayed at a time.)
2. Move the cursor to the FUN tion
will default to CURR as only
. Move the cursor to the VIEW ACE
display mode does not apply
4. Move the cursor to the DAT REL. Absolute display mode
fundamental as a 100 % ref
fundamental. Phase angles
The phase angle of the fund
5. Skip the SCALE field as it o
6. Move the cursor to the TRIG ONT. The SINGLE mode will
acquire the data once and show the result. If you select CONT, the data will be updated
continuously.
3 field and select the TABLE or BAR display mode. The TR
to FFT results.
A MODE field and select ABS or
will show all harmonic components in volts or amps. Relative display mode will use the
erence and display all harmonics as a percentage of the
are always shown with respect to the fundamental frequency.
amental is always shown with respect to phase A.
nly applies to the TRACE display mode.
MODE and select SINGLE or C
128 MX Series
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