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Operation
values. If an input value falls below the bottom of the lowest range
in auto-range mode, or below the bottom of a held range, the display
will begin to flash. Measurements can still be made, but the input is
outside of its specified range and accuracy cannot be guaranteed. If
the input falls to a value too low to actually permit a measurement,
the display will indicate "Input Low".
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.
2.10 Measurement of Frequency
The 918B is capable of displaying any frequency between 45 and
500 Hz. Make frequency measurements with the 918B by using
either the voltage or the current inputs individually. However, if
both have signals present, the instrument will default to reading the
frequency of the voltage input.
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.