Geração e execução automática de testes para programas de controladores lógicos programáveis para sistemas instrumentados de segurança.

Abstract

Safety Instrumented Systems (SIS) are designed to guarantee the industrial system safety preventing undesirable situations when executing procedures performed automatically or by human being. In the context of SIS, ensuring reliable and safe operation is vital because hardware and software faults or human error can cause damage to the plants, humans and the environment. The goal of this work is to present a method to increase reliability and safety in Programmable Logic Controllers (PLC) programs for SIS. Automatic generation and execution of test cases, which include the the system outputs and timer properties states, are used to evaluate whether the SIS program is in conformance to its specification. The Hardware in the loop (HIL) architecture, which supports the dynamic verification of PLC programs for SIS, is used here. Furthermore, timed automata networks together with reduced ordered binary decision diagrams (ROBDD) are used to generate non-redundant test cases. Three case studies are used to evaluate the proposed method and the results attest its efficiency.