A dry powder inhalation device (10) is described comprising a housing (330), an advancement mechanism (400), a displacement sensor (430) that advances in association with continuous advancement of the advancement mechanism, and a transfer component (440) that converts the advancement of the displacement sensor into intermittent motion of a units dose display (450). The displacement sensor has a range of movably engaged positions wherein the displacement sensor movably engages the transfer component, and device further comprises a discrete alignment mechanism (412, 414, 416) capable of moving the displacement sensor backwards to one of a plurality of spatially defined positions that are not within said range of movably engaged positions.
