Fluke 87 TRUE RMS MULTIMETER User Manual page 33

intermittent failures. This mode follows the update time of
the analog display. (The minimum and maximum
excursions of the analog display get recorded.)
The 1 millisecond Peak MIN MAX mode is ideal for
recording transients, especially from intermittent power
lines or connections. This mode can also be used to
measure the + and - peak values of sinewaves up to
about 450 Hz, for easy measurement of both peak line
voltage and line current measurements of power supplies
and electrical equipment.
The high accuracy mode (1 second response time) follows
the digital display and can be selected as a power-on
option by pressing Mwhile turning the meter on. This
mode has the full accuracy of the meter and is best for
recording power supply drift, line (mains) voltage changes,
or circuit performance while line voltage, temperature,
load, or some other parameter is being changed.
Frequency Counter readings are recorded only in the high
accuracy mode
In the MIN MAX Recording mode, the true average of all
readings taken since entering MIN MAX is calculated. The
average value displayed in both the 100 millisecond and 1
second modes is the mathematical integral of the input
(within the response time and accuracy specifications of
the meter). When you display the average, the reading
rate slows somewhat in order to calculate the average of
the accumulated readings.
The average reading is useful for smoothing out unstable
or changing inputs, calculating power consumption (such
as kilowatt hours), estimating the percent of time a circuit
is operational, or verifying circuit performance (or
temperature with the optional 80TK Thermocouple
Module).
If you want to record readings only during the duration of
a particular test (such as during the frequency response
sweep of an audio amplifier, for example), apply the input
signal, start the test (or sweep, in this example), and let
the meter stabilize. Now press M, then press
Iand stop the test. The minimum, maximum, and
average of all readings taken during the test are now held
in memory. Momentarily press Mto scroll to the
reading of interest. Be careful: if you hold down the
Mfor longer than a second, you will exit the MIN
MAX Recording mode and erase the memory. As long as
the rotary switch is not turned and the other pushbuttons
(except REL) are not pressed, these readings will remain
in memory until the battery dies.
Applications
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