Rockwell Automation 1794-OB16D FLEX I/O Diagnostic Modules User Manual - Manual (Page 61)

Publication 1794-UM061A-EN-P - July 2006
Configure Your Adapter and Digital Modules on a ControlNet Network 59
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 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 listed below.
Use this communication format
with a remote ControlNet
communication module:
In these scenarios:
None • All of the 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 of the 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 of the 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.