7-2
IM 253421-01E
Holding the Display
When you use the display hold function and change the order or display function while
the harmonic analysis function is ON, you can display the harmonic data analyzed at the
corresponding time.
Updating the Displayed Data
The display can be updated in the same way as for normal measurement.
Overrange/Error Displays
In case the fundamental frequency of the PLL synchronization signal lies outside the
measurement range. Display B will show “FrqEr”.
Note
The measurement range of the fundamental frequency of the harmonic analysis function is
different from the frequency measurement range of normal measurement. For details, see
chapter 16, “Specifications.”
Display in case of Overrange
The overrange display (being the same as for normal measurement) will appear when
all rms values of the 1st to 50th order reach the following value:
• 140% of the rated range for the 600 V voltage range, or 20 A current range
• 200% of the rated range for voltage ranges except 600 V, or current ranges
except 20 A
The relative harmonic content and harmonic distortion are related to voltage and current.
Error Display
The power factor or phase angle will show PFErr or dEGEr when either the voltage,
range or power exceeds 200% of the range.
Computation Over Display
Appears in the same way as for normal measurement.
Dot Display
The display will show dots in any of the following cases.
• When there are no more analysis data to be displayed during harmonic analysis;
• Soon after the harmonic analysis function has been turned ON;
• When the PLL synchronization is being re-established;
• Until the initial analysis data are obtained, after having changed the settings;
• When the analysis order which depends on the fundamental frequency, exceeds
the upper limit, after having set the order at display A;
• When the display function is set to relative harmonic content (%) and the order at
display A is set to 1;
• When the PLL source is set to voltage, and an attempt is made to display the
current frequency (AHz); or when the PLL source is set to current, and an attempt
is made to display the voltage frequency (VHz);
Averaging Function
Exponential averaging is performed with an attenuation constant of 8.
Output to an External Plotter
Using the GP-IB or RS-232-C interface, harmonic analysis data can be printed as value
or graph on an external plotter.
Effect of Aliasing
This instrument is not equipped with an internal aliasing filter. Due to aliasing accidental
errors may occur under the following circumstances.
Fundamental frequency f in Hz
40
≤
f<70
errors may occur in case of harmonic components of the 256th or higher;
70
≤
f<130 errors may occur in case of harmonic components of the 128th or higher;
130
≤
f<250 errors may occur in case of harmonic components of the 64th or higher;
250
≤
f
≤
440 errors may occur in case of harmonic components of the 32nd or higher.
7.1 Harmonic Analysis Function