Image Number 12 for United States Patent #5119739.
A computer assisted transit car door operating system for augmented automation of transit car door panel operation while providing safety provisions to restrain rail movement unless all passage doorways are closed. A programmable logic controller generates a sequence initiating (opening or closing) signal for a door panel; or, a manual input signal can be introduced for such purpose. The controller receives signals from a panel position sensor and a panel movement sensor to evaluate door panel status and generate status indication and panel movement signals. Automated control of door panel movement is selectively directed to a doorway, or doorways, at which an opening or closing problem is being encountered; that is, the exclusion of door panel movement signals to properly operated door panels. An electrical cam device utilizes a radiant energy emitter and detector with a reversible-direction, coded attenuator, keyed to a reversible-direction motor drive for a door panel; modulating output of such radiant energy detector indicates direction of movement and other data by coordination with the controller. An electrically controlled power regulator controls connection of a source of DC power to control direction of rotation of a reversible-rotation DC motor controlling opening and closing of door panel.