Complex production systems are increasingly using Industrial Ethernet for connecting MES, PLCs, Touch Control, and even sensors and actors within the industrial control network. While today’s production is still process driven under MES control, digitalization requires a data driven approach with cyber physical systems acting autonomously in a connected production world. Moving away from a centralized control architecture has the advantage of more flexibility but eliminates the implicit knowledge on global parameters such as the current condition or state of the overall machinery. This paper describes a methodology to retrieve these global parameters independently from any control system and fully transparent to the control network. A data sensor device is introduced that can listen to any Ethernet data traffic. Together with a specialized packet rules engine it is used to extract and combine information out of a raw Ethernet data stream to build up a virtual sensor device. A production state identification sensor is described as an example application of the virtual data sensor device.