Allen-Bradley 1756-L61 ControlLogix 5561 Programming Manual page 13

Communicate with I/O Modules Chapter 1
Table 2 - Control Input and Output Modules
Controlling This Ownership
Input modules Owner
Listen-only
Output modules Owner
Listen-only
Description
An input module is configured by a controller that establishes a connection as an owner. This configuring controller
is the first controller to establish an owner connection.
Once an input module has been configured (and owned by a controller), other controllers can establish owner
connections to that module. This lets additional owners to continue to receive multicast data if the original owner
controller breaks its connection to the module. All other additional owners must have the identical configuration
data and identical communications format that the original owner controller has, otherwise, the connection
attempt is rejected.
Once an input module has been configured (and owned by a controller), other controllers can establish a listen-only
connection to that module. These controllers can receive multicast data while another controller owns the module.
If all owner controllers break their connections to the input module, all controllers with listen-only connections no
longer receive multicast data.
An output module is configured by a controller that establishes a connection as an owner. Only one-owner
connection is allowed for an output module. If another controller attempts to establish an owner connection, the
connection attempt is rejected.
Once an output module has been configured (and owned by one controller), other controllers can establish listen-
only connections to that module. These controllers can receive multicast data while another controller owns the
module. If the owner controller breaks its connection to the output module, all controllers with listen-only
connections no longer receive multicast data.
Rockwell Automation Publication 1756-PM004D-EN-P - September 2012 11