Publication 1756-PM004C-EN-P - October 2009 13
Communicate with I/O Modules Chapter 1
Use the following table to choose the type of ownership for a module.
There is a noted difference in controlling input modules versus controlling
output modules.
Choose the Type of Ownership
If module is And another controller And you want to Then use this type of connection
Input module Does not own the module Owner (not listen-only)
Owns the module Maintain communication with the module
if it loses communication with the other
controller
Owner (not listen-only)
Use the same configuration as the other
owner controller.
Stop communication with the module if it
loses communication with the other
controller
Listen-only
Output module Does not own the module Owner (such as, not listen-only)
Owns the module Listen-only
Control Input and Output Modules
Controlling This Ownership Description
Input modules Owner 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.
Listen-only 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.
Output modules Owner 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.
Listen-only 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.
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