Chapter 5 Introduction to Data Acquisition in LabVIEW

Figure 5-8. Extracting Waveform Components

Waveform Data on the Front Panel

On the front panel, use the Waveform control, available on the

Controls»I/O palette, or a Waveform Graph, available on the

Controls»Graph palette, to represent waveform data.

Use the Waveform control to manipulate the t0, dt, and Y components of the waveform or display those components as an indicator. Refer to the Waveform Control Components section for more information about each component.

When you wire a waveform to a graph, the t0 component is the initial value on the x-axis. The number of scans acquired and the dt component determine the subsequent values on the x-axis. The data elements in the Y component comprise the points on the plot of the graph.

If you want to let a user control a certain component, such as the dt component, create a front panel control and wire it to the appropriate component in the Build Waveform function.

The VI in Figure 5-9 continuously acquires 10,000 scans from a data acquisition device at a scan rate of 1,000 scans per second, which began at 7:00 p.m. You can control the ∆ t of the waveform.