YOKOGAWA WT500 User Manual page 34

Measurement Range (See section 4.4 for operating instructions)
IM 760201-01E
Set the measurement range using an rms value. When directly applying voltage or
current signals to an input element, two types of measurement ranges are available: fixed
range and auto range. When waveforms are displayed and the crest factor (see section 4.6
for details) is set to 3, the vertical display range corresponds to 3 times the measurement
range. When the crest factor is set to 6, the vertical display range corresponds to 6 times
the measurement range. For details about waveform display, see section 2.7, "Waveform
Display."
Fixed Range
Select each range from the given choices. The selected range does not change even
if the amplitude of the input signal changes. For voltage, the maximum and minimum
selectable ranges when the crest factor is set to 3 are 1000 V and 15 V. When the crest
factor is set to 6, the maximum and minimum selectable ranges are 500 V and 7.5 V.
Auto Range
The measurement range is switched automatically depending on the amplitude of the
input signal. The different ranges used in the auto range are the same as those available
for the fixed range.
• Range Increase
• The measurement range is increased when the data of measurement function
Urms or Irms exceeds 110% of the currently set measurement range.
• The measurement range is increased when the crest factor is set to 3 and the peak
value of the input signal exceeds 330% of the currently set measurement range,
or when the crest factor is set to 6 and the peak value of the input signal exceeds
660% of the currently set measurement range.
• Range Decrease
The measurement range is decreased when the data of the measurement function
Urms or Irms is less than or equal to 30% of the measurement range and Upk
Ipk * are less than or equal to 300% of the next lower range when the crest factor is set
to 3, or 600% of the next lower range when the crest factor is set to 6.
* Even if the NULL feature is on, the values are determined as if though it were off.
Power Range
The measurement ranges (power ranges) of active power, apparent power, and reactive
power are determined by the wiring system, voltage range, and current range as shown
below. For the actual power range values, see section 4.3, "Setting the Measurement
Range during Direct Input."
Wiring System
1P2W (single-phase, two-wire system)
1P3W (single-phase, three-wire system)
3P3W (three-phase, three-wire system)
3V3A (three voltage, three current method)
3P4W (three-phase, four-wire system)
2.3 Measurement Conditions
Power Range
Voltage range × current range
Voltage range × current range × 2
(when the voltage and current ranges on the
elements in the wiring unit are set to the same
range)
Voltage range × current range × 3
(when the voltage and current ranges on the
elements in the wiring unit are set to the same
range)
1
2
3
4
5
6
7
8
9
*
and
10
11
12
13
14
App
Index
2-11