A method and apparatus are provided for writing to a flags register in a pipeline microprocessor. The active surface of the instrument is exposed to cleaning media, which consists of separate, moving particles, enclosed into an instrument container. The frame ground electrode is provided over the stainless steel board and electrically coupled to the stainless board. A second surface portion of the cover is adapted to totally internally reflect a first portion of the light to the first surface portion. Other embodiments include vacuum use attached to the capillary tubes to increase the speed of detection. Therefore the dart does not engage or otherwise affect any of the upstream devices.