Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 39)

Rockwell Automation Publication 1756-UM533C-EN-P - February 2011 39
Chapter
3
ControlLogix Module Operation
Introduction Every I/O module in the ControlLogix system must be owned by a ControlLogix
controller. This owner-controller stores configuration data for every module that
it owns and can be located locally or remotely, relative to the I/O module’s
position. The owner sends the I/O module configuration data to define the
module’s behavior and begin operation within the control system. Each
ControlLogix I/O module must continuously maintain communication with its
owner to operate normally.
Typically, each module in the system has only one owner. Input modules can have
more than one owner. Output modules are limited to a single owner.
By using the Producer/Consumer model, ControlLogix I/O modules can
produce data without having been polled by a controller first. The modules
produce the data and any owner or listen-only controller device can consume it.
For example, an input module produces data and any number of controllers can
consume the data at the same time. This eliminates the need for one controller to
send the data to another controller.
The table explains the topics discussed in this chapter.
Topic Page
Direct Connections 40
Input Module Operation 40
Input Modules in a Local Chassis 41
Input Modules in a Remote Chassis 44
Output Module Operation 46
Output Modules in a Local Chassis 46
Output Modules in a Remote Chassis 47
Listen-only Mode 49
Multiple Owners of Input Modules 49
Configuration Changes in an Input Module with Multiple Owners 51
Unicast Communication 51