14-6
IM 760201-01E
14.5 Accuracy
Voltage and Current Accuracy
tem
Specifications
Accuracy (at 6 months)
Conditions
Temperature: 23 ± 5°C Humidity: 30 to 75%RH. Input waveform: Sine wave. Common-mode
voltage: 0 V. Frequency filter: Set to 440 Hz.
λ
(power factor): 1. Crest factor: 3. After the warm-
up time has passed. Wired condition after zero-level compensation or measurement range
change. f is the frequency.
• Voltage
Frequency
Accuracy
±(reading error + measurement range error)
DC
0.1% of r 0.1% of range
0.5 Hz ≤ f < 45 Hz
0.1% of r 0.2% of range
45 Hz ≤ f ≤ 66 Hz
0.1% of r 0.1% of range
66 Hz < f ≤ 1 kHz
0.1% of r 0.2% of range
1 kHz < f ≤ 10 kHz
{0.1 + 0.05 × (f – 1)}% of r 0.2% of range
10 kHz < f ≤ 100 kHz
{0.5 + 0.04 × (f – 10)}% of r 0.3% of range
* The unit of f in reading-error equations is kHz.
• Current
Frequency
Accuracy
±(reading error + measurement range error)
DC
0.1% of r 0.1% of range
0.5 Hz ≤ f < 45 Hz
0.1% of r 0.2% of range
45 Hz ≤ f ≤ 66 Hz
0.1% of r 0.1% of range
66 Hz < f ≤ 1 kHz
0.1% of r 0.2% of range
1 kHz < f ≤ 10 kHz
(0.1 × f)% of r 0.2% of range
10 kHz < f ≤ 100 kHz
{1 + 0.08 × (f – 10)}% of r 0.3% of range
* The unit of f in reading error equations is kHz.
• For the external current sensor range, add 50
µ
V to the DC current accuracy.
• For the directly applied current input range, add 500
µ
A to the DC current accuracy.
• For the accuracies of waveform display data functions Upk and Ipk:
Add the following values (reference values) to the accuracies listed above.
For the voltage input, add 1.5 ×
1.5×
(15/rated range)% of range
.
For the directly applied current input, add 3 ×
3×
(0.5/rated range)% of range + 5 mA
.
For the external current sensor input, add 3 ×
3×
(0.05/rated range)% of range + 2 mV
.
The effective input range is within ±300% of the range (within ±600% of the range if the crest
factor is set to 6).
• Influence of temperature changes after zero-level compensation or range change
DC voltage accuracy: add 0.02% of range/°C. DC current accuracy: add 500
µ
A/°C. External
input sensor DC accuracy: add 50
µ
V/°C.
• Influence of self-generated heat caused by voltage input
Add 0.0000001 × U
2
% of reading to the AC current accuracies. Add 0.0000001 × U
2
% of reading
+ 0.0000001 × U
2
of range to the DC current and voltage accuracies. U is the voltage reading (V).
Even if the voltage input decreases, the influence from self-generated heat continues until the
temperature of the input resistor inside the WT500 decreases.
• Influence of self-generated heat caused by current input
Add 0.00013 × I
2
% of reading to the AC current accuracies. Add 0.00013 × I
2
% of r 0.006
× I
2
mA to the DC current and voltage accuracies. I is the current reading (A).
Even if the current input decreases, the influence from self-generated heat continues until the
temperature of the shunt resistor inside the WT500 decreases.
• Accuracy changes caused by data update interval
When the data update interval is 100 ms, add 0.05% of reading to all accuracy figures.
• Guaranteed accuracy ranges for frequency, voltage, and current
All accuracy figures for 0.1 to 10 Hz are reference values.
The voltage accuracy figures for 30 kHz to 100 kHz when the voltage exceeds 750 V are
reference values.
The current and 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.
