Common vs. Independent Y-Axes

The Line Graph has a toolbar button that determines whether data values being graphed have common y-axes or independent y-axes. This is a toggle button. The icon on the button changes depending on which mode is currently active as shown below.

Common Y-Axes ( )

When using common y-axes, the same scale will apply to all traces assigned to an axis.  Traces can be assigned to an axis by selecting the trace, right-clicking, and then choosing Assign to Left Axis or Assign to Right Axis. (A trace is selected by clicking on its name in the list above the Edit and Delete buttons.) The scale for the common left y-axis will spread from the lowest value of any trace assigned to the left y-axis to the highest value of any trace assigned to that axis. The scale for the common right y-axis will spread from the lowest value of any trace assigned to the right y-axis to the highest value of any trace assigned to that axis. By default, all traces are assigned to the left y-axis and the scale will spread from the lowest value of any trace being graphed to the highest value of any trace being graphed.

The graph legend will show an L or R next to the name of each trace to indicate whether that trace is assigned to the left or right y-axis.

The default y-axis title will be the name of the data file from which data values are being graphed.

Independent Y-Axes ( )

When using independent y-axes, the scale shown on each y-axis will apply only to the last selected trace that is assigned to that axis. (Traces can be assigned to an axis by selecting the trace, right-clicking, and then choosing Assign to Left Axis or Assign to Right Axis.) The scale will only show the value spread for the specified trace, but all traces will maintain their relative positions on the graph. The y-axis title will be the name of the last selected trace.