Implementation model alternatives for IEC 61499 Function Block networks

The function block (FB) is proposed by IEC 61499 as the basic construct for the development of reusable, interoperable, distributed control applications. The FB design-level construct is clearly described by the standard so various prototype development environments have been developed during last years. However, implementation model issues are not explicitly addressed and this is one of the main reasons for the fact that the FB model has not been yet adopted by industry. In this paper, we describe implementation model alternatives with main focus on the mapping of the FB network constructs to the target execution environment RTOS tasks. Schedulability analysis techniques are also considered to provide a framework for the automatic synthesis of the implementation model. The objective is to guarantee the same standard set of execution semantics independent of the execution environment.