Well Being over Ethernet
Written by Andrew Patterson (Guest Author)
February 2, 2017
One of the larger commercial vehicles present at CES 2017 was the NXP® Smarter World Truck – an 18-wheeler parked right outside the Convention Center. It contained over 100 demonstrations making use of NXP products showing some of the latest innovations in home-automation, medical, industrial and other fields. Mentor Embedded, together with RTI, worked with NXP to set up a medical demonstration that showed data aggregation in real-time from medical sensors.By collecting medical data, and analyzing it in real time, either locally or in a back-office cloud, a much quicker and more accurate diagnosis of any medical condition can be possible. Mentor Embedded’s aggregation gateway made use of the multicore NXP i.MX6, a well-established platform, running our own secure Mentor Embedded Linux®. The technology we specifically wanted to highlight in this example was DDS (Data Distribution Service), implemented by RTI’s Connext® DDS Professional. The DDS communication protocol, based on a physical Ethernet network, allows multiple sensor nodes to link to a hub or gateway, so it is appropriate for many medical and industrial applications where multi-node data needs to be collected securely and reliably.
Traditional patient monitoring systems have made use of client/server architectures, but these can be inflexible if reconfiguration changes are needed, and they don’t necessarily scale to a large number of clients in a large-scale medical or industrial installation. DDS uses a “publisher” and “subscriber” concept – it is easy to add new publishers and subscribers to the network without any other architecture changes, so the system is scalable.
In the publish-subscribe model there is no central data server – data flows directly from the patient monitor source to the gateway destination. In our demo medical system, the data sources are individual sensors that put data onto the Ethernet network when the new readings are available. Data is tagged for reading and accessed by any registered subscriber. Once received by the subscriber gateway, the data can be uploaded to a cloud resource for further analysis and comparisons made with historical readings. Further trend analysis can be made over time.
The process for adding a new node to a publish-subscribe network is straightforward. A new data element announces itself to the network when it attaches, optionally describing the types and formats of the data it provides. Subscribers then identify themselves to the data source to complete the system reconfiguration.
DDS provides a range of communication data services to support a variety of application needs, ranging from guaranteed command and control, to real-time data transmission. For example, if it is required to send a “halt” command to a specific node, there is a data service type that guarantees error-free delivery, so sensor data transmission stops immediately. There are also time-sensitive modes, useful when there is time-sensitive data, which require minimum network latency. Less time-critical data can make use of a “best effort” service, where transmission is scheduled as a lower priority than the time-sensitive communication.
Our demonstration setup is shown in the picture on the left in the NXP Smarter World Truck 2017. The NXP i.MX6 quad core system was linked to a 10” touch-screen display, showing patient graphs. The Mentor Embedded Linux operating system included the RTI Connext DDS protocol stack, the necessary drivers for high-performance graphics, and the Ethernet network connections. Other options include a fastboot capability and wireless communication links for cloud-connectivity. For more information please visit Mentor Embedded Linux.
To see when the NXP Smarter World Truck is coming near you, visit the schedule at iot.nxp.com/americas/schedule – it is being updated frequently, so keep a watch on it!
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