Time-Sensitive Networking: A Key Element of Future Industrial Productivity
Media talk about the Internet of Things (IoT) is usually related to consumer items. It’s much more interesting to the average person to read about smart refrigerators and controlling every device in your house from your smartphone than it is to read about integrating IoT into manufacturing processes. Yet the so-called Industrial Internet of Things (IIoT) is critical to the next stages of economic productivity.
America may be reaching a critical point with industrial productivity. The Bureau of Labor Statistics productivity index shows a slowing of the rate of productivity increase over the last few years and an outright decline over the last two quarters. Some of that slowdown is due to a lack in economic confidence to invest in new equipment, but it’s also possible that the technology that will truly drive productivity isn’t in place yet.
IIoT is in place in some manufacturing environments, but it doesn’t yet have comprehensive standards that would allow for breakout implementation across all industries and applications. Time-sensitive networking (TSN) is a fundamental part of those upcoming standards.
TSN and Determinism
For many of the IoT consumer applications, speed and real-time communication are useful but not critical. Should your refrigerator or thermostat control not receive immediate information or interfere with each other temporarily, it’s easy to correct. In the potential world of high-speed manufacturing, such a problem could be disastrous. Missed connections and millisecond delays in communication between robotic systems can cause product to be literally destroyed—and if the systems must be synchronized to avoid physical collisions, the robotic systems themselves may be harmed.
Thus industrial robotic systems need true determinism, or the ability to send a piece of information to a destination and receive a response in a repeatable timeframe (definition by Mark Cotter, Senior Systems Engineer at ICT Global in a 2001 article). There are two large associated factors: the protocol that is used and the amount of traffic on the network.
The Ethernet backbone itself is non-deterministic, but several protocols such as EtherCAT and PROFINET have brought some level of determinism to industrial applications. Still, the industry lacks an overarching standard, and it’s inevitable that networks will be continually overloaded. As IIoT allows greater levels of connectivity and enables new industrial process automation methods that were never practical before, traffic and bandwidth issues become even more challenging.
Add machine-to-cloud connectivity to allow full information flow and large-scale analysis, and the need for a single set of standards to optimize the flow becomes overwhelming.
Benefits of a TSN-Inclusive Standard
The IEEE TSN networking task group was created in 2012 to address this situation and is currently working on a TSN-specific substandard that falls under the IEEE 802.1 standard. In essence, the group is incorporating the elements of Audio Video Bridging into a comprehensive standard for IIoT, including reserved bandwidth for any one application and the IEEE 1588 Precision Time Protocol that enables precise time synchronization.
Industrial benefits of TSN include layers of reliability improvements such as the ability to set up instantaneous switchover through alternate paths to compensate for equipment failures. However, the real benefit of TSN to industrial applications is in the ease of scalability of processes and the receipt and processing of real-time information for analysis and feedback. That’s where industry can realize major productivity benefits.
With luck, we’ll have a decent time window between TSN’s industrial implementation and the inevitable point when all the newly enabled processes and connected devices load up the system and send us back to the drawing board for the next round of innovation.