The paper describes the application of Grafcet to supervisory, knowledge-based applications. Grafchart, a grafcet-based toolbox has been implemented in the real-time expert system environment G2. The toolbox supports steps, transitions, parallel paths, macro steps, and exception transitions. Several applications of the toolbox are presented. One of these is a full-scale industrial application where Grafchart is used to implement a hydrogen balance advisory control system.