This technology is available from Temarex Corporation.




Inventor(s):J. Welch

Disclosure 164 U.S. Patent 5,777,869

This invention relates to a relay ladder logic (RLL) solver for use with programmable logic controllers (PLC), and belongs to a class of event chaining algorithms.

Events are changes in system model variables.Event chaining algorithms maintain the state of a system model by propagating input changes through the model, processing only the chains of events rather than the entire model.The event sweep algorithm computes all changed flow throughout the ladder, without processing parts of the ladder whose flow is not affected by the scan events.

The algorithm's scan times depend only on the number of input and state changes on a scan.Previous methods have scan times which are dependent on the size of the ladder.The RLL event sweep differs from prior methods in that full information is maintained on the power flow in the ladder.

These algorithms are ideally suitable for simulation or on-line monitoring nodes of operation in which a section of the ladder is observed or captured for interpretation and use by the PLC.This technology is adaptable to any RLL system, having nor formatting restrictions.The speed improvement allows ladder support with a standard microprocessor, integrated with word level functions such as counters, timers, and arithmetic.



Inventor(s):J. Welch

Disclosure 142 U.S. Patent 5,230,061

The invention describes a clause counter map interface engine which is an interpreter method based upon the Boolean form, in which Boolean inference is directly assisted by a programmable data structure.The system provides a translation of a series of Boolean logic functions into a compact map representation, which may then be used for Boolean interface by means of an interpreter algorithm or interface adapted to update function values based upon any changed input value.

The invention provides a rule-based model for logical control systems having an imbeddable, event-chaining inference engine which is independent of the rule-based model.The time to complete a scan cycle of the system depends directly upon the number of inferences in an up-date interval between input and output variable changes, and the lengths of inference chains of events in the logic.

The clause counter map inference engine generally provides a method of implementing logical functions where inferencing is at an optimum, thereby reducing inference processing time and providing a system which may take the place of other on-line control methods for implementation of a PLC, and also may be applied to expert and knowledge-based decision systems which utilize logic programming and rule search methods.

A demonstration is available upon request.