A solenoid with two magnetically separate yoke regions, providing two distinct armature latching positions, is driven by a single effective winding. In one embodiment, the yoke regions consist of U-cores on either side of the armature and a single winding consisting of multiple turns, each turn looping through both U-cores and looping around the ends of the armature. In a second embodiment, distinct winding regions associated with the separate yoke regions are interconnected in series to make a single effective winding. Passage of the armature across a defined central position of minimum inductance is detected electrically, permitting a determination of absolute flux at a position of known inductance and thereby initializing a flux integration over time.