D.3 Process automation
22.2613GPPRelease 18Service requirements for the 5G systemTS
D.3.0 General
Process automation has much in common with factory automation (see clause D.2). Instead of discrete products (cars, chocolate bars, etc.), process automation addresses the production of bulk products such as petrol and reactive gases. In contrast to factory automation, motion control is of limited or no importance. Typical end-to-end latencies are 50 ms. User-experienced data rates, communication service availability, and connection density vary noticeably between applications. Below, we describe one emerging use case (remote control via mobile computational units, clause D.3.1) and a contemporary use case (monitoring, clause D.3.2).
Note that automation fieldbuses (see clause D.2.0) are also used in process automation.
D.3.1 Remote control
Some of the interactions within a plant are conducted by automated control applications similar to those described in clause D.2. Here too, sensor output is requested in a cyclic fashion, and actuator commands are sent via the communication network between a controller and the actuator. Furthermore, there is an emerging need for the control of the plant by personnel on location. Typically, monitoring and managing of distributed control systems takes place in a dedicated control room.
Staff deployment to the plant itself occurs, for instance, during construction and commissioning of a plant and in the start-up phase of the processes. In this scenario, the locally deployed staff taps into the same real-time data as provided to the control room. These remote applications require high data rates (~ 100 Mbit/s) since the staff on location needs to view inaccessible locations with high definition (e.g. emergency valves) and since their colleagues in the control room benefit from high-definition footage from body cameras (HD or even 4K).
For both kinds of applications, a very high communication service availability is needed (99,9999%). Typically, only a few control loops are fully automated and only handful of control personnel is deployed on location, so that the connection density is rather modest (~ 1000 km-2).
D.3.2 Process and asset monitoring
The monitoring of states, e.g. the level of the liquid of process reactors, is a paramount task in process automation. Due to the ever-changing states, measurement data is either pulled or pushed from the sensors in a cyclic manner. Some sensors are more conveniently accessed via wireless links, and monitoring of these sensors via handheld terminals, e.g. during maintenance, is also on the rise. This kind of application entails rather modest user experienced data rates (~ 1 Mbit/s), and since this kind of data is "only" an indicator for, e.g., what process should be stopped in order to avoid an overflow, and not for automated control loops, the requirement on communication service availability is comparably low (99,9%). Note that emergency valves and such are typically operated locally and do not rely on communication networks. However, many sensors are deployed in chemical plants etc., so that connection density can readily reach 10 000 km-2.
D.3.3 Service area
While, for instance, chemical plants and refineries can span over several square kilometres, the dedicated control rooms are typically only responsible for a subset of that area. Such subsets are often referred to as plants, and their typical size is 300 m x 300 m x 50 m.