Industrial networking: Build Ethernet networks using device level ring technology

Rockwell Automation has embedded Ethernet device level ring (DLR) technology into its Integrated Architecture system for high-speed, high-performance applications needing resilient networks, and for machine builders looking for flexible, reliable, low-cost network solutions for their real-time EtherNet/IP applications. Throughout 2009, Allen-Bradley ControlLogix controllers, I/O systems and Allen-Bradley Kinetix motion solutions with DLR technology will be made available. Rockwell Automation will also release a stand-alone communication module to help manufacturers connect devices not equipped with DLR technology to the ring.

DLR is a network technology for industrial applications that takes advantage of embedded switch functionality in automation end devices, such as I/O modules and programmable automation controllers, to enable Ethernet ring network topologies at the device level. Unlike a network- or switch-level ring topology that provides resilience to the network infrastructure, DLR technology adds device-level network resilience to optimize machine operation. When a DLR detects a break in the ring, it provides alternate routing of the data to help recover the network at extremely fast rates. Enhanced diagnostics built into DLR-enabled products identify the point of failure, helping to speed maintenance and reduce mean time to repair.
"Functional tests show that the typical recovery time for a 50-node device level ring is less than three milliseconds," said Mike Hannah, manager, Networks Business, Rockwell Automation. "With this fast recovery, most failures become invisible to devices on the network, and machines often continue operating without interruptions. Keeping production running on the plant floor helps increase machine uptime and productivity—important KPIs for today’s manufacturers."
In addition to superior network recovery performance, Hannah said DLR technology helps simplify network architecture while still providing the flexibility to connect and coexist with other network topologies. Multiport EtherNet/IP devices equipped with DLR technology connect directly to neighboring nodes and form a ring topology at the end devices. DLR technology reduces the number of external components and associated cabling, which eases design and installation for machine builders.

Importance of ring topologies
"Ethernet ring topologies are important for machine control because they help keep production up and running," says Harry Forbes, analyst, ARC Advisory Group. "Using ring topology in machine designs enables machine builders to deliver more robust, easier-to-maintain machines that benefit them and their customers."
ODVA, an international association comprised of members from the world’s leading automation companies, recently extended the EtherNet/IP specification to include the DLR protocol, creating a network solution for multivendor EtherNet/IP systems. By complying with a single standard ring specification, manufacturers using DLR-enabled products can achieve interoperability and numerous benefits provided by the EtherNet/IP network. DLR technology also supports the IEEE 1588 standard for precise time synchronization and standardized Quality of Service (QoS) mechanisms to help prioritize data transmission.
For more information on Rockwell Automation control solutions with DLR technology,

visit www.ab.com/networks/switches/embedded.html .

– Edited by Renee Robbins, senior editor
Control Engineering News Desk

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