7-7
IM WT310E-02EN
Specifications
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7
App
Index
7.3.2 Active Power Accuracy
Item
Specifications
Accuracy
Requirements
Same as the conditions for voltage and current.
• Power factor: 1
Accuracy (at 12 months)
(The accuracy shown below is the sum of reading and range errors.)
* f in the read error equation is the input signal frequency in kHz.
WT310E/WT332E/WT333E
WT310EH (Current EXT sensor input)
WT310EH (Direct current input)
DC
±(0.1% of r 0.2% of range)
±(0.3% of r 0.2% of range)
0.1 Hz ≤ f < 45 Hz
±(0.3% of r 0.2% of range)
±(0.3% of r 0.2% of range)
45 Hz ≤ f ≤ 66 Hz
±(0.1% of r 0.05 % of range)
±(0.1% of r 0.05 % of range)
66 Hz < f ≤ 1 kHz
±(0.2% of r 0.2 % of range)
±(0.2% of r 0.2 % of range)
1 kHz < f ≤ 10 kHz
±(0.1% of r 0.3 % of range)
±[{0.067×(f–1)}% of reading]
±((0.13×f)% of r 0.3 % of range)
10 kHz < f ≤ 20 kHz
±((0.13×f)% of r 0.5 % of range)
10 kHz < f ≤ 100 kHz
±(0.5 % of r 0.5 % of range)
±[{0.09×(f–10)}% of reading]
• Influence of temperature changes after zero-level compensation or range change
Add the product of the voltage influence and the current influence listed below to the DC power
accuracies.
DC voltage accuracy: 0.02% of range/°C
DC current accuracies
WT310E (5mA/10mA/20mA/50mA/100mA/200mA ranges): 5μA/°C
WT310E (0.5A/1A/2A/5A/10A/20A ranges) and WT332E/WT333E direct current input: 500 μA/°C
WT310EH direct current input: 1mA/°C
External current sensor input (/EX1): 1mV/°C
External current sensor input (/EX2): 50μV/°C
• Influence of self-generated heat caused by voltage input
Add 0.0000001 ×U
2
% of reading to the AC power accuracies.
Add 0.0000001 ×U
2
% of r 0.0000001 ×U
2
% of range to the DC power accuracies. U is the
voltage reading (V).
Influence of self-generated heat caused by voltage input lasts until falling the temperature of the input
resistor even if voltage input decreases.
• Influence of self-generated heat caused by current input
WT310E:
Add 0.00013 × I
2
% of reading to the AC power accuracies.
Add 0.00013 × I
2
% of r 0.004 × I
2
mA (0.5 A, 1 A, 2 A, 5 A, 10 A, and 20 A ranges) or 0.00013
× I
2
% of r 0.00004 × I
2
mA (5 mA, 10 mA, 20 mA, 50 mA, 100 mA, and 200 mA ranges) to
the DC power accuracies.
I is the current reading (A).
WT310EH:
Add 0.00006 × I
2
% of reading to the AC power accuracies.
Add 0.00006 × I
2
% of r 0.001 × I
2
mA to the DC power accuracies.
I is the current reading (A).
WT332E/WT333E:
Add 0.00013 × I
2
% of reading to the AC power accuracies.
Add 0.00013 × I
2
% of r 0.002 × I
2
mA to the DC power accuracies.
I is the current reading (A).
Influence of self-generated heat caused by current input lasts until falling the temperature of the shunt
resistor even if current input decreases.
• Guaranteed accuracy ranges for frequency, voltage, and current (direct input)
All accuracy figures for 0.1 Hz to 10 Hz are reference values.
The power accuracy figures for DC, 10 Hz to 45 Hz, and 400 Hz to 30 kHz when the current
exceeds 20 A are reference values.
WT310E only
The maximum current input is 6 A when the frequency is over 30 kHz up to 100 kHz.
7.3 Accuracy
