User manual

Rockwell Automation Publication 1756-UM001O-EN-P - October 2014 177
Redundant Systems Chapter 12
System Requirements
Most redundant systems must use at least these system components. For some
applications, the ControlNet and EtherNet/IP modules are optional.
Table 46 - System Requirements
Quantity Item Notes
2 ControlLogix chassis Both chassis must be the same size.
2 ControlLogix power supply Must be the same in each chassis.
2 ControlLogix controller • Use 1756-L6x or 1756-L7x controllers.
• Use the same catalog number, series, firmware revision, and
memory size controllers in each chassis.
• Same slot placement.
2 ControlLogix ControlNet
communication module
• Use 1756-CN2/B, 1756-CN2R/B, or 1756-CN2RXT modules.
• ControlNet modules in the chassis must be identical in firmware
revision, in series, slot placement, and module type.
2 ControlLogix EtherNet/IP
communication modules
• Use the 1756-EN2T, 1756-EN2TXT, or 1756-EN2TR modules.
• Must be identical in firmware revision, slot placement, and module
type.
2 Redundancy module • Use 1756-RM2 or 1756-RM2XT modules.
• Redundancy modules in the chassis must be identical in firmware
revision and slot placement.
• For L7x high performance systems, RM modules must be RM/B and
must have the same series and firmware revision in the chassis.
1 or 2 Redundancy module cable
(fiber-optic)
• Use the 1756-RMCx cable.
• Standard lengths are available.
2 Additional ControlNet nodes • Place all I/O in remote chassis or DIN rails.
• Add at least two nodes to each ControlNet network and the
redundant chassis pair.
• For enhanced redundancy, you must have at least one
keeper-capable ControlNet device at a node address lower than the
node addresses of the ControlNet modules in the redundant chassis.