Abstract
We document the application of formal methods to the specification and verification of the type of process control typically used in safety critical systems. We discuss the use of an executable subset of the formal specification language OBJ to model and verify systems utilising Programmable Logic Controllers (PLCs) prior to hardware implementation. We specify a stand alone PLC. a common instruction sub-set, and a complete “test engine” combining all the main elements of a PLC, ie. I/O/program scan-I-Program + IO-History. The method integrates with existing techniques for the development of PLC programs which we specify by an abstract data type which models ladder logic. Examples are presented to demonstrate the practicality of the approach and the benefits to be gained from testing such systems in software. The role of such techniques in an industrial safety critical context are discussed, both from the point of view of systems implementation and maintenance. In conclusion we outline current work focusing on hand held tool support, additional formal verification methods, and the application of the technique to systems development within safety standards.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
