Time independent controller for cassette changing apparatus

摘要

A time independent controller for a novel cassette changer is shown. A cassette changer including a plurality of limit switch inputs (210) and means for detecting occurrence of a failure during a change cycle. The total angular displacement of a driving motor is detected (422) and upon reaching a predetermined angle of displacement (437) a test for an appropriate input (418) is provided. In one disclosed embodiment a read only memory (465) determines the controller state (461-463). Apparatus (426, 427, 450) which is responsive only to the limit switch inputs closing in a pair wise proper sequence is also shown.