YOKOGAWA wt3000 - Page 321

12-7
IM 760301-01E
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App
Index
Specifications
Power Accuracy
Item Specifications
Accuracy Conditions
(accuracy at 6 months) Same as the conditions for voltage and current.
Frequency Accuracy
±(reading error + measurement range error)
DC
• Voltage input 0.05% of reading + 0.1% of range
• Current of a 30-A input element
from direct input
• Current of a 2-A input element 0.05% of reading + 0.1% of range
from direct input + 2 µ A × voltage reading
0.1 Hz ≤ f < 30 Hz 0.2% of reading + 0.3% of range
30 Hz ≤ f < 45 Hz 0.05% of reading + 0.05% of range
45 Hz ≤ f ≤ 66 Hz
• Current sensor input 0.02% of reading + 0.04% of range
• Current of a 30-A input element from
direct input
• Current of a 2-A input element from
direct input at the 500 mA to 2 A range
• Current of a 2-A input element from 0.05% of reading + 0.05% of range
direct input at the 5 mA to 200 mA range
66 Hz < f ≤ 1kHz 0.05% of reading + 0.05% of range
1 kHz < f ≤ 10 kHz 0.15% of reading + 0.1% of range
10 kHz < f ≤ 50 kHz 0.3% of reading + 0.2% of range
50 kHz < f ≤ 100 kHz 0.014 × f% of reading + 0.3% of range
100 kHz < f ≤ 500 kHz 0.012 × f% of reading + 1% of range
500 kHz < f ≤ 1 MHz (0.048 × f – 19)% of reading + 2% of range
* The unit of f in the read error equation is kHz.
• For temperature changes after zero level compensation or range change, add (voltage influence) ×
(current influence) to the DC accuracy. For details on voltage and current influence, see page 12-5.
• For self-generated heat caused by current input on an AC input signal, add the following values
to the power accuracy.
• 2-A input element: 0.004 × I
2
% of reading
• 30-A input element: 0.00002 × I
2
% of reading
• For self-generated heat caused by current input on a DC input signal, add the following values to
the power accuracy.
• 2-A input element: 0.004 × I
2
% of reading + 6 × I
2
µ A
• 30-A input element: 0.00002 × I
2
% of reading + 3 × I
2
µ A
I is the current reading (A). The influence from self-generated heat continues until the
temperature of the shunt resistor inside the WT3000 lowers even if the current input changes to
a small value.
• When the data update interval is 50 ms, add 0.1% of reading to all accuracy figures.
• When the data update interval is 100 ms, add 0.05% of reading to all accuracy figures.
• All accuracy figures for 0.1 to 10 Hz are reference values.
• The power accuracy figures for 30 kHz to 100 kHz when the voltage exceeds 750 V are
reference values.
• The power accuracy figures for 100 kHz to 1 MHz when the voltage (V) exceeds 2.2 × 10
4
/ f
(kHz) are reference values.
• The power accuracy figures for DC, 10 Hz to 45 Hz, and 400 Hz to 200 kHz when the current
exceeds 20 A are reference values.
• The power accuracy figures for 200 kHz to 500 kHz when the current exceeds 10 A are
reference values.
• The power accuracy figures for 500 kHz to 1 MHz when the current exceeds 5 A are reference
values.
12.4 Accuracy