Rockwell Automation Allen-Bradley 1794-IB16D - Select a Communication Format

Rockwell Automation Publication 1794-UM061B-EN-P - March 2020 61
Configure Your Adapter and Digital Modules on a ControlNet Network Chapter 6
Select a
Communication Format
When you configure a remote ControlNet communications module or an I/O
module, you select a communication format. The communication format that
you choose determines the data structure for the tags that are associated with the
module. Many I/O modules support different formats. Each format uses a
different data structure.
The communication format that you choose also determines:
• Direct or rack-optimized connection
• Ownership of outputs
For a remote ControlNet communications module, you must select one of the
formats that are listed below.
Use this communication format
with a remote ControlNet
communication module:
In these scenarios:
None • All remote I/O communicating with a controller
via the remote ControlNet communication module
use a Direct Connection communication format.
• The connection is used for scheduled
peer interlocking.
• When I/O will be predominately direct
connections.
• When multiple controllers control the outputs in
the chassis
Rack optimized • Some or all remote I/O communicating with a
controller via the remote ControlNet
communication module use a Rack Optimized
communication format.
• To minimize ControlNet bandwidth when using
large volume of digital I/O.
• If only one controller will control the I/O.
Rack optimized - Listen only • Some or all remote I/O communicating with a
controller via the remote ControlNet
communication module use a Rack Optimized
communication format.
• The connection is going to read inputs but is not
going to be controlling outputs.