Arbiter Systems 931A, Operation Manual

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readings are summed once every second, using the real-time clock, to
produce Energy readings.
3.3.1.4 VA/PF
Setup 4
VA
PF
Press the VA/PF key to display the apparent power and
power factor for signals routed to Channels 1 and 2.
The
input multiplexing circuitry determines which input signals are
connected to the measurement channels, according to selections
made by the operator (refer to Section 3.5.1.2 and 3.5.2.2).
To use the VA/PF function, Channel 1 must be set to mea-
sure AC voltage, and Channel 2 set to measure AC current. Measurements
may be made in either wide-band or narrow-band mode. The power factor
range is between -1 and +1, leading or lagging (see Figure 3.1).
In wide-band mode, apparent power (volt-amps, or VA) is determined
by multiplying the wide-band rms voltage by the wide-band rms current.
Power factor is determined by dividing the wide-band active power by the
wide-band apparent power (refer to Section 3.3.1.3).
In narrow-band mode, apparent power is determined by multiplying the
fundamental amplitude of the voltage and the current (accurately by DSP).
Power factor is the cosine of the phase angle between the fundamentals of
the current and the voltage, ignoring harmonics. The Lead/Lag indication
for Power Factor may be disabled. Refer to Section 3.3.1.13, Menu - Phase
Preference.
Pressing the VA/PF key a second time toggles the display from Power
to Energy. VA-hours are continuously accumulated. Use the RESTART
key to zero the Energy readings. Power readings are summed once every
second, using the real-time clock, to produce Energy readings.
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