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Operation
Hold Mode
When making measurements using any of the operating modes of
the 918B, you can "freeze" the values for all measured parameters
by simply pressing the "HOLD" button. You can then switch
between all of the different modes and determine their respective
values at the time "HOLD" was pressed. Pressing "HOLD" a second
time restores the instrument to normal operation.
Min / Max Readings
Recording of minimum and maximum values is suspended for any
period of time that the hold function is active. However, all
previously recorded values are retained. Refer to section 3.2 for
more information on minimum and maximum value recording.
2.6 Measurement of Volt Amps (Apparent Power)
The value of volt amps (VA) is defined as the product of the rms
voltage and the rms current, without regard to the phase angle.
Using the supplied 1000:1 current transformer, the 918B is capable
of measuring volt-amp values of up to 20,000. (For instructions on
using other current transformers with different ratios, refer to section
2.2.1.1). For volt-amp measurement with the 918B, both the voltage
and the current inputs are utilized.
CAUTION
Do not exceed ±25 volts peak, with respect to earth
ground, on the (-) voltage input. The 918B is designed to operate
with the (-) input connected to earth ground or circuit neutral.
Procedure
1.
To perform VA measurements with the 918B, switch the
instrument to the VA mode by first pressing "SHIFT", then
pressing "VA".
2.
Connect the output of the clamp-on current transformer (CT) to
the current input of the 918B, using the supplied cable. Be sure