2-17
IM WT310E-01EN
Measurement Conditions
1
2
3
4
5
6
7
8
App
Index
2.7 Setting the Crest Factor
Procedure
Follow the procedure indicated by the thick lines in the following menu.
2.
4.
(Display C)
Select the crest factor.
(Display B)
1.
3.
5.
Confirm the setting
and close menu.
Explanation
Crest Factor
The crest factor is defined as the ratio of the peak value of the waveform to the rms value. It is also
referred to as the peak-to-rms ratio.
Peak value
Rms value
Crest factor (CF, peak-to-rms ratio) =
On this instrument, the crest factor indicates the maximum multiple of the measurement range that can
be applied as a peak value. The crest factor can be set to 3, 6, or 6A. The default setting is 3.
When the crest factor is set to 6A, the input range of the measurement range is expanded as follows
as compared to when the crest factor is set to 6. This is used to suppress frequent range changes
when measuring a distorted waveform in auto range mode.
• Condition for increasing the range in auto range mode (for details, see section 2.3).
The voltage or current exceeds 260% of the currently set measurement range.
• Condition that cause an over-range indication (“- - - o L -”) (for details, see section 7.4 in the Getting
Started Guide, IM WT310E-02EN)
The measured voltage or current exceeds 280%* of its rated range.
* 220% for the maximum range (20 A range for crest factor 6) on the WT310EH
Note
• When you set the crest factor and are using fixed ranges, the voltage and current ranges are set to their
maximum values.
• If you set the crest factor when auto range is in use, the voltage and current ranges are set to their
maximum ranges, and then auto range is applied.
• Set the crest factor to six to meet the measurement condition of a crest factor of 5 or greater, which is
required by IEC62018, etc.
• The voltage range, current range, effective input range, and measurement accuracy vary depending on
the crest factor value. For details, see chapter 7 in the Getting Started Guide, IM WT310E-02EN.