considerd in this report. This report focuses only on time-sensitive and real-time applications. 4.3.1 Summary of Real-time Use Cases and Classes of Service The table below summarizes use cases and requirements grouped in three classes of services. The latency bound is defined as the worst-case one-way latency measured at the application layer. The reliability is defined as the percentage of packets expected to be received within the latency bound. Applications and A Class B Class C Requirements Applications Interactive video, AR/VR, remote Hard-real-time soft-real-time HMI, isochronous control, mobile cyclic control, control, motion robotics, machine tools, control, printing, Automated Guided production lines packaging Vehicles (AGV) Time 10-1µs ~1 µs ~1 µs synchronization Latency bound 50 -10 ms 10 1 ms 1ms 250 µs – – Reliability 99% - 99.9% 99.9% - 99.99% >99.999% 4.3.2 Traffic Profiles The communication model of a closed loop control system, described in the figure below, is applicable to many industrial applications. Therefore, its traffic profile can be considered a repenstative model for many industrial systems. The main traffic patterns generated by a control system include: Periodic data: this is the typical pattern generated by remote IO (sensing and actuation) within a closed loop control system. Remote HMI devices can also operate as a remote IO device and generate peridic data. The data sizes are usually fixed and relatively small (e.g typicall from 30 to 300 bytes). The periodic data, which may be exchanged in uplink (sensor to controller) or downlink (controller to actuator) direction, is expected to be delivery within a give latency bound. Request/Response: these are asynchronous messages. The request is typically generated by the HMI device and response is generated by the controller device.
considerd in this report. This report focuses only on time-sensitive and real-time applications. 4.3.1 Summary of Real-time Use Cases and Classes of Service The table below summarizes use cases and requirements grouped in three classes of services. The latency bound is defined as the worst-case one-way latency measured at the application layer. The reliability is defined as the percentage of packets expected to be received within the latency bound. Applications and Requirements A Class B Class C Applications Interactive video, soft-real-time control, mobile robotics, Automated Guided Vehicles (AGV) AR/VR, remote HMI, cyclic control, machine tools, production lines Hard-real-time isochronous control, motion control, printing, packaging Time synchronization 10-1µs ~1 µs ~1 µs Latency bound 50 -10 ms 10 – 1 ms 1ms – 250 µs Reliability 99% - 99.9% 99.9% - 99.99% >99.999% 4.3.2 Traffic Profiles The communication model of a closed loop control system, described in the figure below, is applicable to many industrial applications. Therefore, its traffic profile can be considered a repenstative model for many industrial systems. The main traffic patterns generated by a control system include: Periodic data: this is the typical pattern generated by remote IO (sensing and actuation) within a closed loop control system. Remote HMI devices can also operate as a remote IO device and generate peridic data. The data sizes are usually fixed and relatively small (e.g typicall from 30 to 300 bytes). The periodic data, which may be exchanged in uplink (sensor to controller) or downlink (controller to actuator) direction, is expected to be delivery within a give latency bound. Request/Response: these are asynchronous messages. The request is typically generated by the HMI device and response is generated by the controller device.
11-18-2009-00-0rta-rta-report-draft.docx