Vertical And Horizontal Axes - YOKOGAWA DL7440 User Manual

2.2

Vertical and Horizontal Axes

Vertical Sensitivity <For the setup procedure, see section 5.2>
Vertical Position of the Waveform <For the setup procedure, see section 5.3>
2-2
The vertical sensitivity setting is used to adjust the displayed amplitude of the waveform
for easy viewing. The vertical sensitivity is set by assigning a voltage or a current value
to one grid square (1 division) on the screen. By switching attenuators with different
attenuation and changing the amplification of the pre-amplifier, the sensitivity changes in
steps (for example, voltage sensitivity changes in steps as in 1 V/div, 2 V/div, and 5 V/
div). In addition, by computing the digital data of the waveforms acquired at the vertical
sensitivity described above, the waveforms can be displayed by setting the sensitivity to
0.4 (or 0.5) to 10 times the vertical axis setting that was used to acquire the waveforms
(Variable).
If 1.00 V/div is changed to 0.500 V/div
Vertical
position
mark
GND level
mark
Note
Vertical Sensitivity Setting and Measurement Resolution
To measure the voltage with high accuracy, set the vertical sensitivity so that the input signal
is measured with as large an amplitude as possible. The DL7400 uses 8-bit A/D converters
to sample the input signal at a resolution of 255 levels (LSB). On the screen, the waveforms
are displayed using 24 levels per division on the grid.
Valid Data Range
Assuming that the output value from the A/D converter is in the range of 0 to 255, the data
point at the center of the screen corresponds to 128 of the A/D output. However, because the
full range of the A/D converter is 255 levels, the 256
addition, the DL7400 handles the output values of the A/D converter as 0s and 1s. Therefore,
the valid data range of the DL7400 is approximately ±5.29 divisions from the center of the
screen. If the vertical axis position is moved after stopping data (waveform) acquisition, the
valid data range also moves by the same amount.
Since the DL7400 is capable of displaying 8 channels (4 channels on the DL7440) of
input waveforms, the waveforms may overlap making them difficult to be observed. In
this case, you can change the display position of waveforms along the vertical axis
(vertical position) in the range of ±4 divisions for easier viewing. The vertical sensitivity
switches around the vertical position (mark).
Position 0.00 div
Vertical position
mark
1 div = 1.00 V
th
level on the screen is not used. In
Position 2.00 div
Position –3.00 div
1 div = 0.500 V
IM 701450-01E