In order to change the color of the same line in a graph, you will actually have to graph a segment of the line for each different color.
For instance, if you want to graph values of 0-90 in blue, you would use a Plot function with the x values ranging from 0-90 and the corresponding y values. In another posting you said you were using PlotXvsY, so the xdata parameter would have the values from 0 to 90 and the ydata parameter would have the y data.
Then change the plot color and call PlotXvsY again and plot with the xdata parameter with data contents from 91 to 100 and ydata would have the y values for those x data points.
For multiple lines on a graph, you would just repeat the process for each line and each color segment.
Hope that helps!
Shannon R
.
Applications Engineer
National Instruments