CONTROLLER PROGRAMMABLE WITH LOGIC INSTRUCTIONS REPRESENTATIVE OF CIRCUIT NODES AND ELEMENTS OF A LADDER DIAGRAM

摘要

A controller for electrical circuit systems and apparatus, the controller being programmable with logic instructions representative of circuit nodes of a ladder diagram. As compared to the prior art, this controller is simple to program and does not require any modification of the conventional ladder diagram. The controller comprises a store WNM of the logic values of the circuit nodes and a store CCM of the logic values of the control coils in the ladder diagram. The control program is stored in main memory MM. Processing circuit LC1 is provided for computing and updating the logic values of the circuit nodes or control coils based on the previous stored values and input signals from input circuit IB, and for storing the updated logic values in the stores WNM and CCM.