A lithographic apparatus has a plurality of patterning arrays, which are spaced apart in an object plane. A incident beam reaches the first grating where it is diffracted in two beams whose directions are interchanged by the second grating, the resulting beams being then again diffracted by the first grating in an output diffraction direction where they interfere together. A third switch terminal is mounted on the housing and has a pair of third contact portions engageable by the first and second contact portions of the first and second switch terminals, respectively, in response to inserting a memory card into the card-receiving space. The method further includes accumulating the delta samples over the time period in accordance with the sample rate, calculating a field size based on a maximum one of the delta samples, and writing the delta values to the database using the calculated field size. The method also includes retrieving information regarding a first work area associated with the person of interest and reproducing a section of a floor plan containing at least the first work area. The cuff may be generally cylindrical or may be tapered.