Rockwell Automation Publication 56RF-UM001A-EN-P - October 2011
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EtherNet/IP Addressing
Chapter 4
Device Level Ring (DLR)
Topology
A DLR network is a single-fault tolerant ring network intended for the
interconnection of automation devices. DLR topology is advantageous as it can
tolerate a break in the network. If a break is detected, the signals are sent out in
both directions. When this topology is used, both EtherNet connections are
used. The network connection to Link 1 or Link 2 does not matter.
Rockwell Automation recommends that you use no more than 50 nodes on a
single DLR, or linear, network. If your application requires more than 50 nodes,
we recommend that you segment the nodes into separate, but linked, DLR
networks.
With smaller networks:
•
there is better management of traffic on the network.
•
the networks are easier to maintain.
•
there is a lower likelihood of multiple faults.
Additionally, on a DLR network with more than 50 nodes, network recovery
times from faults are higher. The maximum cable length between devices cannot
exceed 100 m (328 ft).
For more information on setting up and configuring a DLR network, please refer
to ENET-AP005.
Figure 11 - DLR Topology
RFID
Interface
Block
RFID
Transceivers
RFID
Transceivers
RFID
Interface
Block