A system and method for moving a flowable substrate through a chamber is provided. These vectors may be stored as a vector table in a data memory that is accessible by both the firmwaresoftware and the hardware component. The proportional trim current is then fed back to the reference current to provide a trimmed temperature compensated reference current. The first end of the radial members can be connected at a hub. Neuromuscular stimulation assemblies, systems, and methods may include a steerable introducer that defines an interior lumen sized and configured to shield a percutaneous electrode from contact with tissue during advancement to a desired position within tissue.