Abstract: An elevator system including at least one elevator car mounted for movement in a building to serve the floors therein, and pushbuttons for entering calls for elevator service. Calls for elevator service initiated by the pushbuttons are visually displayed in a predetermined order on a display in which the display positions for such calls are not specifically related to a specific floor, but which may be used to indicate a call associated with any floor of the building. In a preferred embodiment, the calls are stacked or compressed to provide a predetermined uniform physical spacing between adjacent calls of the predetermined order. The predetermined order and predetermined spacing are maintained as new calls are entered on the display, and answered calls are deleted therefrom.

Abstract: An elevator system with an asynchronous-synchronous interface between the system processor and each car controller. Each interface includes a serially accessed memory which intermittently receives command words from the system processor. The serially accessed memory repetitively reads out the commands to the car controller, and updates the commands in response to a new data word without interrupting the flow of data to the car controller. Each interface utilizes internal logic and timing for controlling its serially accessed memory, thus relaxing the memory capacity and processing speed requirements of the system processor.

Abstract: An elevator system having a plurality of elevator cars mounted in a building to serve the floors therein. Supervisory control for the elevator cars includes first and second strategies for providing special service to first and second floors, respectively, of the building. The first and second strategies are selectively enabled, the floors to which the strategies are to be applied are selectable, the position of the door of an elevator car parked at the first or second special floor is selectable, the service direction of a car parked at the first or second special floor is selectable, and a predetermined relationship in priority between the first and second special floors is provided when both the first and second strategies are simultaneously enabled.

Abstract: An elevator system for a building having a plurality of floors, including supervisory system control for controlling a plurality of elevator cars to answer calls for elevator service from the plurality of floors. The system control assigns unassigned service directions from the plurality of floors to each of the elevator cars, until meeting a predetermined dynamic limiting average. The assignments are made to one car at a time, proceeding to the next when a predetermined limiting average is met. The order in which the cars are selected for assignment is a dynamic order, responsive to the relative work loads of the cars. The assignments are made to each car, starting in a predetermined direction from each car's position, and are terminated a predetermined travel distance from the car, if not terminated sooner due to a limiting dynamic average. A predetermined minimum limiting dynamic average may be set, to control the rate at which idle cars become busy cars when traffic increases.

Abstract: An elevator system including supervisory system control for controlling a plurality of elevator cars to answer calls for elevator service. The supervisory system control, using information provided by the cars, groups the floors of a building, and service directions therefrom, into sets, each of which indicates those floors and service directions served by the same combination of in-service elevator cars. The supervisory system control periodically determines, for each set, the average number of floors and service directions therefrom, and the average number of calls, per in-service elevator car serving the set. The supervisory system control then assigns floors and service directions therefrom to the cars, using these averages, to substantially equally distribute the floors, and service directions therefrom, for each set, among the elevator cars serving the set, as well as to substantially equally distribute the calls for elevator service among the elevator cars.

Abstract: An elevator system having a plurality of elevator cars mounted in a building to serve the floors therein. Supervisory system control periodically assigns service directions from the floors to the elevator cars by dividing the service directions among the elevator cars within the constraint of at least one predetermined dynamic limiting average responsive to a predetermined parameter of the elevator system. A predetermined travel distance limitation may also be applied to at least certain of the elevator cars. A traffic level detector indicates when the traffic demand in a predetermined service direction reaches a predetermined level. When the traffic level detector indicates the traffic in the predetermined direction is at this level, the effect of the constraint, or constraints, is modified to allow more elevator cars to receive service direction assignments in the predetermined service direction.

Abstract: Position measurement apparatus which utilizes a digital code to accurately determine the position of a movable body along a travel path. The digital code is selected to provide, for any N consecutive bits of the code, a bit pattern which is unique. Indicia defining the code, and a reader, are arranged for relative motion in synchronism with movement of the movable body. Translating apparatus converts each combination of N consecutive bits read by the reader into an address defining the location of the movable body relative to the travel path. In a preferred embodiment, the digital code is a maximum length digital code, which is conveniently generated by a polynomial generator. The bit length of the code, which is equal to 2.sup.N -1, is selected according to the length of the travel path and the desired resolution.