The clause counter map: an event chaining algorithm for online programmable logic

Abstract

The clause counter map method (CCM) is a software inference engine for programmable logic systems, including logic controllers and knowledge-based information systems. It provides efficient realizations of synchronous sequential machines using two-valued or three-valued logic. CCM permits the use of general purpose processors for large on-line control models. The CCM interpreter is designed to trade space for time. A redundant state is maintained in a compact map form. Logical events percolate through an otherwise static model. This mode of operation distinguishes the class of event chaining algorithms. Prior on-line methods repeatedly reconstruct or test unchanging portions of the model. In large models, CCM can exceed binary decision machines in speed and require less space. Contemporary modeling languages can be translated into CCM models. Thus event chaining implementation is available for control models defined by relay ladder logic, state machines, function charts, and Petri nets. >