Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 51)

Rockwell Automation Publication 1756-UM533C-EN-P - February 2011 51
ControlLogix Module Operation Chapter 3
Configuration Changes in
an Input Module with
Multiple Owners You must be careful when changing an input module’s configuration data in a
multiple owner scenario. When the configuration data is changed in one of the
owners, for example, Controller A, and sent to the module, that configuration
data is accepted as the new configuration for the module. Controller B continues
to listen, unaware that any changes were made in the module’s behavior.
Unicast Communication Use unicast EtherNet/IP communication to reduce broadcast network traffic.
Some facilities block multicast Ethernet packets as part of their network
administration policy. You can configure multicast or unicast connections for
I/O modules by using RSLogix 5000 software, version 18 or later.
Unicast connections do the following:
• Allow I/O communication to span multiple subnets
• Reduce network bandwith
• Simplify Ethernet switch configuration
Input Module
Configuration
Data
Xxxxx
Xxxxx
Xxxxx Input Module
Configuration
Data
Xxxxx
Xxxxx
Xxxxx
Modified Configuration Initial Configuration
Controller A Controller B Input Module
CTR A CTR B
Controller B is unaware that changes were made by Controller A.
Multiple Owners with Changed Configuration Data
41056
IMPORTANT A dialog box in RSLogix 5000 software alerts you to the possibility of a
multiple owner situation and lets you inhibit the connection before
changing the module’s configuration. When changing configuration for a
module with multiple owners, we recommend the connection be
inhibited.
To prevent other owners from receiving potentially erroneous data, you
must follow these steps when changing a module’s configuration in a
multiple owner scenario while online:
•
For each owner-controller, inhibit the controller’s connection to the
module, either in the software on the Connection tab or the dialog
box warning of the multiple owner condition.
•
Make the appropriate configuration data changes in the software, as
described in the RSLogix 5000 software section of this manual.
•
Repeat steps 1 and 2 for all owner-controllers, making the same
changes in all controllers.
•
Disable the Inhibit box in each owner’s configuration.