The IEC 61499 standard and its semantics

The article is structured as follows. In the "System-Level Design for Distributed Automation" section, we give a general introduction to IEC 61499 in terms of its value for the automation systems developer. In the "Elements of IEC 61499 Architecture" section, the basic elements of the IEC 61499 architecture are presented using an illustrative example. The semantic problems of IEC 61499 are outlined in the "Semantic Problems of IEC 61499" section. The "Semantics of a Basic FB" section focuses on the problems and solutions related to the basic function block (FB) behavior. It is followed by the "Semantics of FB Networks" section that discusses semantic problems related to composite FB structures. In the "conclusions" section, we list some open problems.