Industrial automation systems (IASs) are traditionally developed using a sequential approach where the automation software, which is commonly based on the IEC 61131 languages, is developed when the design and in many cases the implementation of mechanical parts have been completed. However, it is claimed that this approach does not lead to the optimal system design and that the IEC 61131 does not meet new challenges in this domain. In this paper, a system engineering process based on the new version of IEC 61131, which supports Object Orientation, is presented. SysML and UML are utilized to introduce a higher layer of abstraction in the design space of IAS and Internet of Things (IoT) is considered as an enabling technology for the integration of Cyber and Cyber-physical components of the system, bringing into the industrial automation domain the benefits of these technologies.