4-8
IM 760301-01E
Note
•
The range is set in reference to the RMS value of the input signal. For example, if a 100-Vrms
sinusoid is to be applied, set the range to 100 V.
•
When measuring a signal other than a sine wave such as a distorted wave, accurate
measurements can be obtained by selecting the smallest measurement range that does not
meet the conditions below.
•
The input peak over-range indicator at the top center of the screen illuminates or blinks.
•
The measured values of the voltage and current indicate over range [-OL-].
•
The peak over-range indicator may not illuminate or blink in the following cases.
•
If the pulse width is narrow, and the peak value of the waveform cannot be acquired at the
sampling rate of the WT3000 (approximately 200 ks/S).
•
If the high frequency components of the pulse waveform attenuate due to the bandwidth
limiting by the WT3000 measurement circuit and the waveform peak value is less than the
peak over-range detection level.
•
For the list of the range settings of all input elements, see section 3.16, “Displaying the Setup
Parameter List.” You can change the measurement range with the list displayed.
• Auto Range
When
AUTO
is pressed, the AUTO key illuminates and auto range is enabled. The
range switches automatically depending on the magnitude of the input signal as
described below. The different ranges used in the auto range are the same as
those available for fixed range.
• Range Increase
• When the voltage/current mode is RMS, the measurement range is increased
if the data of measurement function Urms
*1
or Irms
*1
exceeds 110% of the
current measurement range.
• If the peak value of the input signal exceeds 330% or 660% of the current
measurement range when the crest factor is set to 3 or 6, respectively, the
range is increased.
• If all the installed input elements are selected (all the element indicators are
illuminated), the measurement range is increased on all input elements when
the range increase condition above of any input element is met.
• When a wiring unit is configured, the measurement range is increased on all
input elements in the wiring unit when the range increase condition above of
any input element in the wiring unit is met.
• Range Decrease
When the voltage/current mode is RMS, the range is decreased if the data of
the measurement function Urms
*1
or Irms
*1
is less than or equal to 30% of the
measurement range and Upk and Ipk is less than or equal to 300% or 600% of
the next lower range when the crest factor is set to 3 or 6, respectively.
*1 When the voltage/current mode is MEAN, DC, or RMEAN, the measurement functions
are Umn and Imn, Udc and Idc, or Urmn and Irmn, respectively.
• If all the installed input elements are selected (all the element indicators are
illuminated), the measurement range is decreased on all input elements
when the range decrease condition above of all input elements is met.
• When a wiring unit is configured, the measurement range is decreased on all
input elements in the wiring unit when the range decrease condition above of
all input elements in the wiring unit is met.
Note
When non-periodic pulse waveforms are applied during auto range, the range may not remain
constant. If this happens, use the fixed range setting.
4.3 Setting the Measurement Range for Direct Input