Rockwell Automation Allen-Bradley ControlLogix 1756-EN2F

Rockwell Automation Publication 1756-UM004C-EN-P - June 2021 39
Chapter 3 Connect Redundant EtherNet/IP Adapters
Redundant Architecture The following figures show DLR and Star Topology with the 1756-EN4TR
module. DLR provides higher resiliency than a single star. Linear topologies
are not recommended because any break or firmware flashing of devices in the
line causes loss of communications to downstream devices.
Figure 9 - Redundant 1756-EN4TR Adapters in DLR Topology
Redundant adapters can be used in a star configuration, as shown in Figure 10.
However, the switch at the center of the star is a single point of failure. DLR
provides for higher resiliency.
Logix5575
Redundancy Module
PRI COM OK
OKFORCE SDRUN
R
U
N
R
E
M
P
R
O
G
Logix5575
Redundancy Module
PRI COM OK
OKFORCE SDRUN
R
U
N
R
E
M
P
R
O
G
1756-EN2TR
(can also be a 1756-EN4TR)
1756-EN4TR pair
Configure all DLR devices on the ring to be at the same speed on all links as
defined in the Deploying Device Level Ring within a Converged Plantwide
Ethernet Architecture design and implementation guide, ENET-TD015
.