Rockwell Automation 1756-RMxx ControlLogix Enhanced Redundancy System User Manual - Manual (Page 40)

40 Rockwell Automation Publication 1756-UM535D-EN-P - November 2012
Chapter 2 Design an Enhanced Redundancy System
Reserve Consecutive Node Addresses for Partner Modules
Where ControlNet modules are used as partners in redundant chassis, plan
consecutive node numbers for those partnered modules. Plan for consecutive
node addresses because the redundant system automatically assigns the
consecutive node address to the secondary ControlNet module.
For example, partnered ControlNet modules with address switches set at 12 are
assigned ControlNet node numbers 12 and 13 by the system.
Figure 7 - Example of Redundant ControlNet Modules at Consecutive Addresses
TIP The primary chassis always assumes the lower of the two node addresses.
CH2 CH1 OK CH2 CH1 OK
Node 12 Node 13
ControlNet Module Switches
Primary Chassis Secondary Chassis