Automatic search facility for microfilm reader - uses microprocessor to execute instructions from keyboard to control projector step motors operations

摘要

The microfilm reader projector contains a platform which is moved in two perpendicular directions and controlled by two step motors controlled from a keyboard console. The keyboard contains several buttons whose functions are identified by a circuit followed by an interface circuit prior to entry to a microprocessor. The microprocessor executes instructions corresponding to the buttons operated to direct signals to control circuits (50X, 50Y) for the motors to allow them to be driven in either direction as required. An alpha numeric display allows display of the function being executed.