Industry 4.0 and Internet of Things (IoT) concepts for streamlined production depend on capable networking and communication technologies require services to communicate with each other directly, and products to control themselves, instead of "top-down" communication from the ERP system via MES, PLC, and ultimately down to the sensor.
In conventional control architectures data requests are initiated either cyclically or are event-triggered, always in response to requests "from above," i.e. from the client level. The lower level always acts as a server and responds accordingly.
In the Smart Factory, physical, real systems and virtual, digital data merge to form intelligent, self-organizing production units that acquire the data needed for this purpose autonomously. This means that all devices and services must be able to communicate with each other independently, irrespective of the manufacturer, operating system, hierarchy, or topology. This controller integrates OPC UA client function blocks; as an OPC UA client, the controller can play the active, leading part, in addition or as an alternative to the conventional role allocation.
The PLC is thus able to exchange complex data structures horizontally with other controllers, or it can vertically call methods in an MES/ERP system via an OPC UA server, e.g. to retrieve new production orders or write data to the cloud. This enables the production line to become autonomously active. In combination with integrated OPC UA security, this is a key step in the movement towards Industry 4.0.
