To overlay plots which have different intervals between the data points you have to create two plots, overlay them and then alter the range of the X and Y axis so that they match. This can be achieved as follows:

A. Select the first data column to be plotted ensuring that you select all of the columns with data of the same interval. (Tip: Hold down the Ctrl key to select individual columns).

B. Create a 2D Line with scatter plot

C. Next, select the columns which have been measured at a different interval taking care not to include the columns that were selected in step (3).

D. Create a 2D Line with scatter plot

E. Move the first graph onto the second graph and align the two plots by clicking on Format > Arrange Graphs > Overlaid

F. In Object Explorer, select one of the graphs X-axis and change the Range from Auto / Auto to the appropriate range e.g. 0 to 24 and similarly for the X-axis on the second graph you have created.

G. In Object Explorer, select one of the graphs Y-axis and change the Range from Auto / Auto to the appropriate scale and similarly for the Y-axis on the other graph. (Tip: the Object Explorer can also be used to change other aspects of the plot e.g. labels on the axes).

The above example assumes that you have a single dataset which contains data measured at two different intervals, however the above procedure could also be applied to a dataset containing three or more different measurement intervals e.g. three columns of measurements where the data intervals are set to a different number of hours for each.