SECTION 4
OPERATION
35
4.3.1.1 WAVEFORM ANALYSIS (continued)
(OPTION- Harmonic Analysis and Synthesis)
The
Va
,
Vb
or
Vc
key will light the Phase LED to select which phase is to be updated or displayed. Only one
phase can be analyzed at a time. Pressing the
+/-
key will toggle between current and voltage parameters.
Pressing the HELP key displays the hotkey list.
The
CLEAR
key will return the display back to the V/I meter.
The
ENTER
key begins the analysis function. The UPC will measure the selected signal, and calculate and
update the harmonic data in memory. This may take some time, depending on the number of samples
analyzed (see the
EDIT
key function below). A beep is heard when the update is complete. Only the
parameter and phase selected as above is updated. Other parameters are retained. All parameters are
then retained until power-off or the memory is cleared.
Harmonic content is displayed as percent of fundamental by default. For display of harmonics by absolute
value, use the EDIT function as shown below.
Pressing
EDIT
allows the user to select the number of samples used during the analysis process. Use the
+/-
key to select the setup preferences.
HARMONIC ANALYSIS SETUP
CHANNEL: CURRENT (USE +/- TO TOGGLE)
CONTENT DISPLAYED AS: % OF FUNDAMENTAL
SAMPLES TO ANALYZE: 128
The value of “nnn” may only be one of the numbers listed below.
If any other number is entered, the default value of 128 will be used.
nnn
number of
harmonics
displayed
number of
harmonics
calculated
Time of
calculation
(approx.)
512
51
256
19 sec.
256
51
128
8 sec.
128 (default)
51
64
4 sec.
64
32
32
2 sec.
32
16
16
1 sec.
16
8
8
.5 sec.
Press
ENTER
after typing this number to store the value.
The default is 128. That allows a full display of 51 harmonics with minimum processing time. Values of 256
or 512 will increase accuracy of the displayed harmonics, at a cost of processing time. Lower values (64, 32,
16) calculate faster but have decreased resolution.
Press
DISPLAY
to return to the harmonic data screen.
Press
EXECUTE
to process new harmonic analysis data.
The display will always show 51 harmonic positions. For calculations which generate fewer harmonics, the
upper harmonic data will be zeros (0).
The full harmonic data set, up to the 256
th
harmonic, is available through the communication port. See
), Metered Data Queries,
:MEASure:SPECTrum:VOLT1[:MAGnitude]
:MEASure:SPECTrum:PHASe.
