INTEGRATED CIRCUIT CONTROLLER PROGRAMMABLE WITH UNIDIRECTIONAL-LOGIC INSTRUCTIONS REPRESENTATIVE OF SEQUENTIAL WIRE NODES AND CIRCUIT ELEMENTS OF A LADDER DIAGRAM

摘要

INTEGRATED CIRCUIT CONTROLLER PROGRAMMABLE WITH UNDIRECTIONAL-LOGIC INSTRUCTIONS REPRE SENTATIVE OF SEQUENTIAL WIRE NODES AND CIRCUIT ELEMENTS OF A LADDER DIAGRAM A programmable controller that may be programmed to simulate a ladder diagram and being operable in response to input signals electrically to control output devices in accordance with the ladder diagram program and comprising, in addition to a main memory that stores the program and a logic processor and input/output circuits, of a special wire number memory and a control coil memory incorporated in the logic processor for receiving, storing and making available to the processor the result of every logic function representing the current on-off status of each wire node(or numbered connection) in the ladder diagram as the program is repeatedly executed and the result of every Logic function representing the current on-off status of each control coil and for retrieving such status each time that an instruction involving a contact of such control coil is read as the program is repeatedly executed. This architecture of the controller affords the maintenance of a complete current record of the changing status of the control coils and their interconnecting circuit nodes. This makes possible a particularly simple unidirectional-logic programming mode, because, in effect, the result of every logic operation is stored away and is repeatedly executed and as changes occur due to the application of input signals so that the programmer does not have to determine which logic operations must be temporarily stored and keep track of which have been stored. The maintenance of such a complete record also affords a powerful monitoring means in that signal tracing can be accomplished by merely calling up predetermined wire numbers from the special wire number memory and displaying the status thereof, or calling up predetermined input devices or control coils to view the status thereof. Moreover, for maintenance purposes, this architecture provides a selectors switch and logic circuitry whereby a predetermined wire node may be manually forced "on" or "off" for maintenance purposes or the like.