This depends on your application. With a PANdrive with sensOstep encoder you have an absolute encoder. So it is possible to calibarate the PANdrive using just the encoder, e.g. at first move to a specific encoder position after starting up. But please note that on every PANdrive the zero point of the encoder is at a different position (as the magnets cannot be fixed at the same position on every motor).
If you have some kind of home switch (also called reference switch) in your application then this can be used for calibration, and you won't need to use the sensOstep encoder for this purpose. Another way of homing would be to use stallGuard for this purpose (but this is also application specific).