The graphical modeling language GRAFCET is used as a formal specification language in industrial control design. This paper proposes a structural analysis that approximates the variable values of GRAFCET to allow verification on specification level. GRAFCET has different elements resulting in concurrent behavior, which in general results in a large state space for analyses like model checking. The proposed analysis approach approximates that state space and takes into consideration the entire set of GRAFCET elements leading to concurrent behavior. The analysis consists of two parts: We present an algorithm analyzing concurrent steps to approximate the step variables and we adapt analysis means from the field of Petri nets to approximate internal and output variables. The proposed approach is evaluated using an industrial-sized example to demonstrate that the analysis is capable of verifying behavioral errors and is not limited by the specification size of practical plants.

翻译：图形化建模语言 GRAFCET 在工业控制设计中用作形式化规范语言。本文提出了一种 structural 分析方法，通过近似 GRAFCET 的变量值，实现规范层面的验证。GRAFCET 包含多个导致并发行为的元素，通常会使模型检测等分析面临巨大的状态空间。所提出的分析方法对该状态空间进行近似处理，并全面考虑导致并发行为的全部 GRAFCET 元素。该分析由两部分组成：我们提出了一种分析并发步进的算法，以近似步进变量；同时，我们借鉴 Petri 网领域的分析手段，近似内部变量和输出变量。我们通过一个工业规模的实例对所提方法进行评估，结果表明该方法能够验证行为错误，且不受实际工厂规范规模限制。