A system for refilling a multi-chamber implantable infusion device is presented. The infusion device has a refill chamber which is accessible through an external septum of a refill port. The refill chamber is divided by an inner septum into an upper reservoir and a lower reservoir. The lower refill chamber is refilled with lower reservoir needles having a needle opening axially placed to align with the lower reservoir. The upper reservoir is refilled with an upper reservoir needle having an opening aligned with the upper reservoir. Magnetic portions are provided in the needles to localize and identify the needle. A processor within the infusion device is connected to magnetic field sensors which sense magnetic portions of the needle and recognize information encoded magnetically within the needle.
