For some industrial applications, the downside of Ethernet has been its lack of true determinism. Though this issue has been addressed by many industrial Ethernet protocols, when it comes to connecting standard IT Ethernet to operations’ Ethernet networks—a type of connection that is increasing across industry—data traffic issues created by these merged networks can impede control system communications and negatively impact production.
That’s where Time Sensitive Networking (TSN) comes into the picture. This developing IEEE standard enhances standard Ethernet to address competing network traffic issues. (The video below explains the TSN standard. You can also read more about TSN here).
Explanation of the TSN Standard
With the TSN standard largely defined (you can follow the standard’s development here), the next step is to put it in the hands of engineers across industry to prove its capabilities. At National Instruments’ NI Week 2016 event, the first available TSN-enabled controller and supporting platform was introduced via collaboration between NI, Cisco and Intel.
This early access technology platform, as NI refers to it since it’s not yet an official product release, includes CompactRIO controllers featuring Intel Atom processors and Intel’s i210 TSN-enabled network interface card. The controller uses LabView system design software to maintain synchronized time to the network and expose that time to code running on the real-time processor, as well as the code running on the FPGA.
Todd Walter of NI pointed out that, since LabView was designed with time as a core concept, it simplifies the process of tightly coordinating signal processing, control algorithms and I/O timing with scheduled network transmission and between multiple systems distributed across a network.
Paul Didier of Cisco highlighted the key Ethernet enhancements provided by TSN:
- Precise time synchronization for 802.1AS, which leverages IEEE 1588 Precision Time Protocol to support synchronization of multiple data streams; and
- Combine time synchronization with traffic management to deliver latency guarantees, i.e., each switch identifies time critical data packets and puts them in a special queue. These packets are forwarded at specific times to create a network flow between the talkers and listeners across the network.
When it comes to the convergence of IT and operations networks, optimization is based on access to data—whether it is on Ethernet or fieldbus, said Walter. “Convergence means having the data open and running on the same network. TSN enables this because with it you can mathematically prove network characteristics to determine how data will flow,” he said. “And with LabView you can tell specific devices to share data and at what rate and then send that information to a centralized network configurator to direct how parameters on the devices need to be set” to avoid any network data collisions and drop outs.
The video below shows a demo of TSN using the early access technology to show how control data is delivered reliably even when transmitting on a merged IT/OT network flooded with HD video data.
TSN Demo at NI Week 2016
Organizations already using this early access technology platform include WZL Aachen for precision machining applications, EUV Tech for semiconductor market tools focused on extreme ultraviolet lithography; and Oak Ridge National Laboratory (ORNL) for electrical smart grid research.
Mark Buckner of ORNL explained at NI Week that ORNL has been working with the new platform for the past three months and has already demonstrated its potential in stabilizing control of the power grid to address the instabilities created as power companies look to incorporate more use of renewable energy sources. “We are demonstrating how Time Sensitive Networking can enable an unprecedented level of microgrid coordination and control, significantly increasing the resiliency of power delivery systems.”
