Use the Picture Plots VIs to create common types of graphs using the 2D picture control. These graphs include a polar plot, a waveform graph, an XY graph, a Smith plot, a radar plot, and a graph scale.

The Picture Plot VIs use low-level drawing functions to create a graphical display of your data and customize the drawing code to add functionality. These graphical displays are not as interactive as the built-in LabVIEW controls, but you can use them to visualize information in ways the built-in controls currently cannot. For example, you can use the Plot Waveform VI to create a plot with slightly different functionality than built-in waveform graphs.

Using the Polar Plot with Point Options VI as a SubVI

Use the Polar Plot with Point Options VI to draw specific, contiguous quadrants of a polar graph or the entire graph at once. As with the built-in LabVIEW graphs, you can specify the color of the components, include a grid, and specify the range and format for the scales.

The Polar Plot with Point Options VI provides a large amount of functionality in a single VI. Consequently, the VI includes complicated clusters for inputs. You can use default values and custom controls to decrease the complexity of the VI. Instead of creating the default cluster input on the block diagram, copy a custom control from the Simple Polar Plot VI in the labview\examples\Graphics and Sound\Picture Plots directory and place it on the front panel.

Using the Plot Waveform and Plot XY VIs as SubVIs

Use the Plot Waveform VI, which emulates the behavior of the built-in waveform graph, to draw waveforms in a variety of styles, including points, connected points, and bars. As with the built-in waveform graphs, you can specify the color of the components, include a grid, and specify the range and format for the scales.

The Plot Waveform VI provides a large amount of functionality in a single VI. Consequently, the VI includes complicated clusters for inputs. You can use default values and custom controls to decrease the complexity of the VI. Instead of creating the default cluster input, copy a custom control from the Waveform and XY Plots VI in the labview\examples\Graphics and Sound\Picture Plots directory and place it on the front panel.

The Plot XY VI and the Plot Multi-XY VI are similar to the Plot Waveform VI. You use different controls to specify the cosmetic appearance of the plot because the XY plotting VIs have three additional plot styles—two scatter plot styles and a plot style where a line is drawn at each unique x -position to mark the minimum and maximum y -values for that x -value.

Using the Smith Plot VIs as SubVIs

Use the Smith Plot VIs to study transmission line behavior, such as in the telecommunications industry. A transmission line is a medium through which you transmit energy and signals. A transmission line can be a wire or it can be the atmosphere through which a signal transmits. Transmission lines have an effect on the signal that is transmitting. This effect, called the impedance of the transmission line, can attenuate or phase shift an AC signal.

The impedance of the transmission line is a measure of the resistance and the reactance of the line. The impedance, z, is commonly listed as a complex number of the form z = r + j x, where both resistance r and reactance x are components.

Use the Smith Plot VIs to display impedances of transmission lines. The plot consists of circles of constant resistance and reactance.

You can plot a given impedance, r + j x, by locating the intersection of the appropriate r circle and x circle. After you plot the impedance, use the Smith Plot VIs as visual aids to match impedance and to calculate the reflection coefficient of a transmission line.

The Smith Plot VIs provide a large amount of functionality in each single VI. Consequently, many of these VIs include complicated clusters for inputs. You can use default values and custom controls to decrease the complexity of the VIs. Instead of creating the default cluster input, copy a custom control from the Smith Plot example VIs in the labview\examples\Graphics and Sound\Picture Plots and place it on the front panel.

To avoid losing detail in the Smith plot, use the Normalize Smith Plot VI to normalize the data. You can pass the data you normalize with the Normalize Smith Plot VI directly to the Smith Plot VI. You usually scale Smith plot data with respect to the characteristic impedance (Z0) of the system.