Fluke 8845A, User Manual

Page: 56 / 103

8845A/8846A
Users Manual
3-14
To make an mX+B calculation:
1.
Press
J
.
2. Press the
MATH
soft key.
3. Press the
€X+B
soft key.
To enter the M value:
4. Press the
€X
soft key
To select the digit to adjust, press either
<--
or
-->
.
With the desired digit selected, press the soft key labeled
--
to decrement the digit
or
++
to increment the character.
5. Press
ENTER
to enter the M value.
6. Press
B
to return to the MX+B menu.
To enter the B value:
7. Press the
B
soft key.
To select the digit to adjust, press either
<--
or
-->
.
With the desired digit selected, press the soft key labeled
--
to decrement the digit
or
++
to increment the character. The right most character is the multiplier. This
character can be set to p, n,
μ
, m, k, M, or G.
8. Press the
ENTER
soft key.
9. Press
B
to return to the MX+B menu.
10. Press the
ENABLE
soft key to start MX+B calculations.
ENABLE
stays highlighted, and all displayed values are the measured value modified by
the formula MX+B.
Pressing
ENABLE
again disables MX+B, and
ENABLE
is no longer highlighted. The
MX+B calculation is applied after other MATH scaling calculations, but before other
MATH comparisons.
Using TrendPlot
TrendPlot provides a visual representation of the measured signal over time. About three-
quarters of the Meter’s display is used to plot the maximum and minimum readings
vertically, while the horizontal axis represents time. The vertical and horizontal axis’ are
not calibrated, and only represent relative time and amplitude depending on the input
signal.
Each plot mark is a one pixel-wide vertical line that represents the highest (top of mark)
and lowest (bottom of mark) reading the Meter has taken in the time since the previous
mark was made. The left-most plot mark represents the time TrendPlot was started. When
all available plot points across the plot area are filled, the Meter compresses the plot
marks to one-half of the plot area. The compression process takes the highest and lowest
reading between every two plot marks, and makes a single plot mark representing the
highest and lowest readings of the two combined plot marks. Future plot marks added to
the end of the compressed display are now the Meter’s highest and lowest readings, taken
over a time period twice as long as the period before the compression.
If the amplitude of the measured value exceeds the positive or negative range of the
vertical axis, the Meter adjusts the vertical range to accommodate the range of the new