Hz - Frequency Measurement; Thd - Harmonic Distortion Measurement; - Df% : Distortion Factor; - Cf : Crest Factor - Chauvin Arnoux F 21 Mode D'emploi

- SMOOTH : smoothed value
First press on this button: SMOOTH is displayed.
The digital value of the measured quantity is smoothed (average over 3 seconds), which
has the effect of damping display instability for fluctuating signals.
The SMOOTH mode operates for all the measured quantities.
- PEAK : peak value
Second press on this button : PEAK is displayed.
The displayed digital value is the instantaneous peak value (1ms) of the current A PEAK or
the voltage V PEAK.
The RECORD mode is accessible for the max value of peak: MAX PEAK.
NB : The bargraph gives the current PEAK value : current or voltage.
Hz : frequency measurement
- Press this button once: Hz is displayed.
The digital display gives the frequency of the current or the voltage.
The bargraph continues to indicate the current RMS value: current or voltage.
NB : The range selection of the digital display is still automatic. Pressing the RANGE button
sets the trigger threshold (see Electrical Specifications).
- Press the button a second time: return to the main function, current or voltage.
THD : distortion measurement
This button allows, by successive presses, measurement of the total harmonic distortion
THD%, the distortion factor DF%, the crest factor CF and return to the main function, current
or voltage.
- THD% : Total Harmonic Distortion
First press on the button : THD% is displayed.
The digital display gives the value in % of the total harmonic distortion.
The bargraph continues to indicate the current RMS value: current or voltage.
NB : The THD% qualifies the total presence of harmonics (up to the 25th) in relation to the
fundamental component of the signal.
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- DF% : Distortion factor

Second press on the button: DF% is displayed.
The digital display gives the value in % of the distortion factor.
The bargraph continues to indicate the current RMS value: current or voltage.
NB : The DF% qualifies the total presence of harmonics (up to the 25th degree) in relation
to the true rms value of the signal.

- CF : Crest factor

Third press on the button: CF is displayed.
The digital display gives the value of the crest factor.
The bargraph continues to indicate the current RMS value: current or voltage.
NB : The CF is the ratio of the peak value over the true rms value of the signal. For reference
the CF of a sinusoidal signal is 1.414.

MAX/MIN : Recording of max/min

This button allows you to access recording mode and, by successive presses, to record the
max, min, average values and current value.
- RECORD : Record
Press this button once: RECORD is displayed and flashes: P is also displayed: operation
is continuous.
The clamp records the min and max values, and calculates the true average value since the
start of the recording. The duration of the recording can be more than 24 hours.
The digital display and the bargraph continue to give the RMS current value.
At each new max or min recorded, a second signal is emitted.
NB : The recording mode is possible on A, V, Hz, THD%, DF% and CF.
If SMOOTH mode is switched On before recording, the smoothed values are recorded.
On RECORD-THD and DF mode service life is limited to 8 hours.
- MAX: reading max
Second press on this button : MAX is displayed.
The digital display gives the max value recorded.
The bargraph continues to gives the current RMS value with a flashing bar to display the
max.
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