In PowerFlow, there are two rotation values for each module.

Primary Rotation

The Primary Rotation is the rotation initially created when the module is added to the layout by one of the populate commands, or by dragging a run. This is reset when recalculating a run with keys like W, E and R.

Secondary Rotation

The Secondary Rotation is a rotation value set and modified by the commands in the Modify | Rotate menu. These rotation angles can be set to achieve a specific layout, while allowing them to be remain relatively constant if and when a section of modules is made to flow along a different path by using keys such as W, E or R.