Infusion pump device and method for improved dosing

An infusion pump device comprising a primary liquid medicament reservoir, a pump with a secondary reservoir to retrieve medicament from the primary reservoir and to subsequently dose the medicament from the secondary reservoir in adjustable volumes (Vdose,i) to a downstream conduit and a control unit to control the operation of the infusion pump device is presented. For metering the volumes (Vdose,i), the control unit causes the infusion pump device to: (a) determine a maximum refill level (VC,max) for the secondary reservoir, based on external parameters, wherein the maximum refill level does not exceed the maximum capacity of the secondary reservoir; (b) fill the secondary reservoir with medicament from the primary reservoir to the maximum refill level (VC,max); (c) meter and convey the medicament volumes to the downstream conduit; (d) if the secondary reservoir becomes empty, refill the secondary reservoir as in step (b) and continue with step (c).