Patent attributes
Drug delivery device comprising expelling means allowing a user to set a dose corresponding to a number of increments from an initial state, an indication member adapted to rotate in a first direction corresponding to the set dose, and rotate in an opposed second direction corresponding to an expelled dose, the indication member having an initial rotational position corresponding to both the initial state and the fully expelled dose state. Sensor means having an incremental counter synchronized with the rotational position of the indication member and having a reference point corresponding to the initial rotational position of the indication member. After detecting an error state the sensor means is adapted to re-synchronize by detecting the number of rotational increments for a set dose and for a subsequent expelled dose. If the numbers are identical the reference point is reset corresponding to the current rotational position of the indication member.
