Table of Contents
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OPERATION
3.13 MATHEMATICAL
FUNCTIONS
The Model 194 has a number of built in mathematical func-
tions that can be used to analyze a measurement.
These
functions
include:
AVG (Average)
TRMS (True Root Mean Square)
PEAK (Positive and Negative Peak Values)
PK TO PK (Peak to Peak)
STD DEV (Standard Deviation)
INTEGRAL
WAVEFORM (Display sample at trigger point)
MATH BUTTONS
The keys associated with the mathematical
functions
are
operational
only when the instrument
is in the single-
channel display mode. However, either channel may be
programmed
for a particular
function
before placing the
instrument
in the dual-channel
mode. To do so, use the
CHANNEL
button
to display the desired channel
and
select the desired function.
Once the function
is selected,
place the unit in the dual-channel
display mode with the
CHANNEL
button.
These mathematical functions operate on the samples CUT-
rently
stored in the measurement
buffer. Samples are
numbered
0 through
n-l, where n is the programmed
number of samples in the measurement. If the instrument
is in the single-trigger mode, selecting a function will cause
that function
to operate on the most recent measuremrnt
sequence. Thus, by taking a single measurement sequence,
you can apply a variety of differerent
math functions
to
a single measurement.
Note, however, that only o"c' func-
tion can be in operation at any given time; selecting a ne\\
mathematical
function
will cancel the previously
selected
function.
It is not possible, for example, to take the integral
of the standard deviation.
Once a function is selected, you can perform that particular
function
a number of times for different
mea~urenwnts
simply by triggering
the instrument.
Each time the unit
is triggered, the measurement buffer will bc updated, the
selected mathematical
operation will be performed on th<a
new measurement,
and the result will be shown on tht,
display.
If the zero mode is in effect for a particular
channel. the
zero baseline value will be subtracted from the reading
after the function
is performed.
1" every mode, the result
will be overrange if one or II~TC' samples is overrange~
Display messages associated with the various math tunc~
tions are summarized
in Table 3.9. The indicated \~alucs
are, of course, typical, and will depend on the measure-
ment on which the particular function is being performed
If a valid measurement
is not present in the buffer, the
reading portion
of the display will contain dashes.
NOTE
The display update rate may vary defending
cjn
the selected math function.
Table 3-9. Math Function Display Messages
Function
Display
Message*
AVG
-1.2345V AVG 1
TRMS
'1.2345V RMS 2
PEAK
1.2345V PK+2
PEAK
1.2345V I'K-'I
PK TO PK
1.2345v P-P 1
STD DEV
O.lOlZV STD 1
INT
4.0315EOOO VS 2
WAVEFORM
2.5931V DC T2
Description
Average of Readings
True RMS of Readings
Display
positive peak value.
Display negative peak value.
Peak-to-Peak Value.
Standard Deviation
Integral of Measurement
Display sample at trigger
point.
*Displayed
value depends on applied signal
3-29
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