1-13
IM 253710-01E
Functions
1
Measurement Range of Voltage, Current, and Power
«For procedures, see section 5.3.»
When directly inputting voltage or current signals to the input module, there are two
types of measurement ranges : fixed range and auto range. When displaying the
waveform, the measurement range corresponds to the vertical display range. For
waveform display, see section 1.6 “Waveform Display.”
Fixed range
Select the range from a list of choices. The selected range does not change even if
the amplitude of the input signal changes. For the voltage of the power measurement
module, the maximum and minimum selectable voltages are “2000 Vpk” and “30 Vpk,”
respectively.
Auto range
The measurement range changes automatically depending on the amplitude of the
input signal. The different ranges are the same as those available for the fixed range.
Note that when the measurement function of the power measurement module is set
so that the numerical data are not measured or computed (when the Measure Mode is
OFF), you can select auto range. However, the range does not change in this case.
Power range
The measurement range (power range) of active power, apparent power, and reactive
power of the power measurement module are determined by the wiring method,
voltage range, and current range as follows. For the actual numerical values of the
power range, see section 5.3 “Setting the Measurement Range during Direct Input.”
Wiring Method
Power Range
1P2W (single-phase two-wire)
voltage range
×
current range
1P3W (single-phase three-wire)
voltage range
×
current range
×
2
3P3W (three-phase three-wire)
(when the voltage and current ranges on the
3V3A (three-voltage, three-current)
corresponding elements are set to the same range)
3P4W (three-phase four-wire)
voltage range
×
current range
×
3
(when the voltage and current ranges on the
corresponding elements are set to the same range)
Scaling «For procedures, see section 5.5.»
When inputting current signals to the power measurement module via an external current
sensor or inputting voltage or current signals via the external PT (potential transformer)
or CT (current transformer), the transformation ratio and coefficient can be specified.
When inputting current signals via an external current sensor
The output of current sensors, such as shunts and clamps, can be input to the current
sensor connector of the power measurement module and be measured. Set how
many mV the current sensor outputs when 1 A of current flows (transformation ratio).
Then, the input signal can be made to correspond to the numerical data or display
data that are obtained when the current is directly applied to the input terminals.
Measurement Function
Transformation
Data before Conversion
Conversion
Ratio
Result
Current I
E
I
S
(current sensor output)
I
S
/E
Active power P
E
P
S
P
S
/E
Apparent power S
E
S
S
S
S
/E
Reactive power Q
E
Q
S
Q
S
/E
Max./Min. current value Ipk
E
Ipk
S
(current sensor output)
Ipk
S
/E
1.3 Acquiring Data (Voltage and Current Signals)