Measurement Computing WavePort 312P rev.1.0 - Manual (Page 47)

PowerVista/312 User’s Manual Device Configuration 4-13
Figure 4-13. Calibration Configuration Dialog.
Items in the Calibration Configuration Dialog include:
• Gain Multiplier: is a number between -1,000,000 and 1,000,000, which is multiplied directly into all voltage and
current magnitudes. Care should be taken to appropriately specify this number since it will have a direct impact
on all measurements involving the given channel.
• Phase Adder: is a phase angle between -360 and 360 degrees, which modifies phasor currents as well as phasor
and RMS power calculations. This correction is used mostly to compensate for phase angle error in clamp-on
current transducers. Note that for real and reactive RMS power calculations, an assumption has been made
regarding phase correction. By applying this fundamental frequency phase correction to total RMS powers, we are
assuming that the fundamental frequency is the dominant contributor to the calculated RMS power, i.e. other
harmonic power components are insignificant. For even severe penetration of harmonic currents this assumption
will hold true since harmonic currents are generally a pure reactive current (penalizing total power factor). As
seen in Table 8 below, even 30% penetration of harmonic reactive power results in low errors when there are up to
20 degrees gross harmonic phase error in a current transducer.