Appendix 2 Measurement Accuracy And Measurement Error - UNI-T UTE310 User Manual

User's Manual
Apparent Power (S /VA)
Reactive Power (Q /var)
Power Factor (PF)
Frequency (fU, fI /Hz)
Peak Factor (Ucf, Icf)

Appendix 2 Measurement Accuracy and Measurement Error

The measurement instruments have certain requirements for measurement accuracy or measurement error.
The measurement accuracy of UTE310 digital power meter has different requirements for different
frequency measurement signals.
For example, the voltage and current accuracy in the range of 45 Hz to 66Hz is ± (0.1% of reading + 0.05 % of
range).
Measurement error of voltage and current

Example 1 Using 1A range to measure the current of 60Hz 1A
Reading error: 1×0.1%=0.001A
Range error: 1×0.05%=0.0005A
The displayed error of measuring 1A current is the sum of reading error and range error, which is
±0.0015A, so the displayed value between 0.9985A ~1.0015A are within the error allowable range.
Example 2 Using 5A range to measure the current of 60Hz 1A
Reading error: 1×0.1%=0.001A
Range error: 5×0.05%=0.0025A
The displayed error of measuring 1A current is the sum of reading error and range error, which is
±0.0035A, so the displayed value between 0.9965A~1.0035A are within the error allowable range.
Instruments.uni-trend.com
S=Urms ⋅ Irms
Q=- �� ,或Q= ��
2 2 2
− �� − ��
��
PF =
Urms ⋅ Irms
Measuring the voltage
frequency (fU) and current
frequency (fl) by zero crossing.
UPK IPK
,Icf =
Ucf =
Urms Irms
UTE310 Digital Power Meter
2
UPK=|Upk＋| or |Upk-|, take the
larger value between the both.
IPK=|Ipk＋| or |Ipk-|, take the larger
value between the both.
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