An Ontology-based Semantic Model Of PLC Programs For Code Exchange And Software Reuse

Regarding the development of Programmable Logic Controller(PLC)in industrial control area,encouraging code exchange and software reuse,as well as implementing more intelligent code retrieval,are necessary to increase the productivity and safety of industrial automation.However,differences between implementations are significant even though all manufacturers claim to conform to the IEC 61131-3 standards,resulting in incompatibilities inside heterogeneous systems,preventing projects from interoperating between vendors.It is then necessary to design a computable knowledge model to semantically represent,organize,and utilize these diversified resources.Using the ontology technique is a common way to achieve the interoperability of heterogeneous systems.In this paper,specific work on the computable semantic model of PLC is as follows.Firstly,we provide a layered PLC ontology and a tool for translating PLC programs to an ontological knowledge base.High-level semantics of PLC projects are added into the ontology including software resources,which can be required for software reuse leveraging semantic query.Secondly,we propose a multi-facets ontology matching approach for PLC domain ontologies,aiming to transfer the PLC projects across heterogeneous platforms without much additional effort.Though using the ontological semantic model raises heterogeneity problems to a higher level,conflicting ontologies in the same domain usually cannot interoperate with each other.Therefore,the ontology matching approach intends to enable the knowledge and data expressed in the matched ontologies to interoperate with each other.Finally,we put forward a novel generation methodology based on code reuse.We provide an ontology-based approach that utilizes semantic code search in a knowledge base transformed from PLC code repository.The semantics of PLC software,hardware,and control logic have been extracted and represented to support semantic queries leveraging SPARQL Protocol and RDF Query Language(SPARQL).Through the case studies,it is demonstrated that the PLC ontology model,the ontology matching method,and the generation method are useful for PLC code exchange and software reuse,which can be applied to improve the PLC programming efficiency.