Cyber-physical systems show their impacts in many areas including industrial automation. Design and analysis of cyber-physical automation systems requires an integral model that takes into account tight coordination of control, communication and physical plants dynamics, thus creating a new research domain, namely industrial cyber-physical systems. This paper proposes a new execution semantics for the IEC 61499 standard that is based on the concepts of discrete-event systems augmented with timestamping of events to guarantee real-time constraints for industrial cyber-physical systems. The proposed execution semantics is implemented in an IEC 61499 execution environment and a case study on building automation systems is used to verify the results.