Instruction manual

3 Display 27
Note: Any changes to the default view, will also be made to the preferences and vice-versa.
Channel Sizing
Figure 3-8: The height of the data displays for four channels in the Main window as set by the default setting (top), and after the
handle for Channel 1 was slid down (bottom).
In addition to scaling the height of the signal to fit in a given channel area, the amount of
display area allotted to each channel in the Main window can be controlled by clicking and
dragging on the top of the channel bar. To change the allocated space for a channel, click on the
top of the channel bar and drag it up or down (Figure 3-8 on page 27).
Converting
Units
When used with WPI or National Instruments hardware, the DataTrax2 software functions as a
calibrated voltmeter, which means the software will accurately display the exact voltage that the
user presents to the analog-to-digital converter. The displayed (and default) units will always be
Volts. While this is useful in many cases, it is not always the most appropriate unit.
If the DataTrax2 software is used to record the output of a transducer designed to measure a
physical parameter, such as force or pressure, other units are more appropriate. In these cases,
Volts can be changed into milligrams or grams. The DataTrax2 software can handle these
conversions easily, provided that the function (or transducer) that relates voltage to real units is
linear.
The first step in converting voltage input to real units is to record a portion of data at two
known values. In the case of a force transducer, record output at two known forces such as zero
and 100 grams. The recorded trace may look something like Figure 3-9 on page 28.