Xcelsius 2008 introduced a global dual axis chart capability that works quite well. I put together a simple example below, illustrating the technology. A dual axis chart is relevant when you are trying to draw indirect correlations between two different measures. I have never seen an effective use of dual axis charts where same measure is displayed on both y axis. The Y Axis toggle in Xcelsius is locate in the general tab for most vertical oriented charts.

Here are a few best practices that make these charts easier to visually digest in Xcelsius:

1. Always include vertical axis labels for the left and right Y axis.
2. Always show the legend on the top or bottom of the chart to ensure there is enough room for both vertical axis labels and titles.
3. Use colors that make it easy to differentiate between each series.

Download Source Files