Select A Communication Format - Rockwell Automation Allen-Bradley ControlNet 1734-ACNR User Manual

Select a
Communication Format
When you configure a remote ControlNet communication 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 communication module, you must select one of the
formats listed in the table Communication Formats.
Table 4.1 Communication Formats
Use This Communication
Format with a Remote
ControlNet Communication
Module
None
Rack optimized
Rack optimized - Listen only
In These Scenarios
• 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
• 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.
• 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.
Publication CNET-UM001C-EN-P - November 2005
Control I/O 4-3