Take the Fast Lane to Automated Driving
The classic automation pyramid model shows a series of well-defined layers structured in such a way that information flows upwards from devices to enterprise via levels of control, supervision and management. Although the model is well-established, this flow of data is by no means smooth. At each layer of the pyramid there are differing functional requirements, this has led to the development of task-specific communication methods which offer little compatibility between the layers.
This issue is particularly acute at the lower end of the model. For field level devices with real-time and safety requirements, the lack of a single suitable communication standard has led to a multitude of competing proprietary protocols. This means that there is incompatibility not only between layers but also within the device and control layers. As a result it is not uncommon for automation devices to support five or more different industrial protocols in order to be compatible with the system favored by the end user.
The separation of real-time and safety sub-systems from the wider automation and IT infrastructure makes it very difficult to access data, limiting the effectiveness of open architecture initiatives such as Industry 4.0. How then can we satisfy these two seemingly competing desires, protecting critical traffic at the same time as providing open data access to all?
Flattening the Pyramid
The structure of the automation pyramid model has come under increasing pressure from users demanding improved connectivity and flexibility. In order to offer field level data more directly, equipment owners have turned to the open OPC UA standard. This provides a model where OPC UA ‘clients’ at management or enterprise levels can request data directly from OPC UA ‘servers’ at the device layer.
Although OPC UA breaks down some of the barriers between automation and IT, it does not solve the issue of the proprietary and isolated networks used for real-time and safety sub-systems. These networks are now addressed with the advent of a Publish/Subscribe model for OPC UA, and the Time Sensitive Networking (TSN) extension which adds real-time functionality to IEEE 802 Ethernet. The combination of OPC UA Publish/Subscribe with TSN enables the exchange of data from one-to-many and many-to-many in real-time over standard Ethernet. OPC UA TSN therefore provides an open, standard and real-time communication platform which supports the principles of the Internet of Things whilst fulfilling the strict requirements of traditional automation.
Removing the arbitrary constraints of the automation pyramid model will precipitate an opening up of the industrial automation market similar to that seen in enterprise IT in the 1990s or IP telephony in the 2000s. Industrial manufacturers and end users will have access to cheaper, interoperable components from a wide range of vendors, with a large pool of engineers available to service them.
A flexible communication infrastructure enables the deployment of new technologies such as fog computing (cloud services at the edge) and innovative ‘as a service’ business models. In industrial automation these developments have the potential to dramatically improve overall productivity and drive growth whilst also offering a chance for new-market entrants and start-ups to disrupt the status quo.
Simon Brooks, Product Marketing Manager Industrial, TTTech