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User Manual
84 i Series / iX Series
the MEAS key may not always bring up the selected screen immediately. There will be a
perceptible delay. This will prevent the screen from appearing with invalid or blank readouts.
The measurement method for voltage and current will depend on the power source operating
mode. The following table shows the return value type (rms or average) and method of coupling
when the measurement command is initiated with a different extension at various operating
modes (AC, DC or AC + DC).
Measurement
Extension
and Coupling Operating Mode
AC DC AC + DC
AC rms rms rms
DC rms rms average
Coupling AC DC DC
4.5.3 Accuracy Considerations
Any measurement system has a finite accuracy specification. Measurement specifications are
listed in Section 2. When using the AC source for measurement purposes, always consider these
specifications when interpreting results. Measurement inaccuracies become more pronounced
as the signal being measured is at the low end of the measurement range. This is particularly
relevant for low current measurements. The i and iX Series are high power AC sources
optimized for providing and measuring high load currents. When powering low power loads,
measurement inaccuracies on rms and peak current measurements will greatly affect derived
measurements such as power, power factor and crest factor.
The measurement system on the i and iX Series uses a data acquisition system with a 20 kHz
bandwidth. This means that high frequency components of the measured signal are filtered out.
Any contribution to the rms value of voltage and current above this cutoff frequency will not be
reflected in the i and iX Series measurements. When using an external measurement reference,
this may account for discrepancies in readings.