Rockwell Automation 1794-OB16D FLEX I/O Diagnostic Modules User Manual - Manual (Page 85)

Publication 1794-UM061A-EN-P - July 2006
Configure your Digital Module on an EtherNet/IP Network 83
RPIs are only used for modules that produce data. For example a local
EtherNet/IP communication module does not require an RPI because it is not
a data-producing member of the system; it is used only as a bridge.
In Logix5000 controllers, I/O values update at a period that you configure via
the I/O configuration folder of the project. The values update asynchronous
to the execution of logic. At the specified interval, the controller updates a
value independently from the execution of logic.
Set the RPI only as fast as needed by the application. The RPI also determines
the number of packets per second that the module will produce on a
connection. Each module has a limit of how many packets it can produce per
second. If you exceed this limit, the module cannot open any more
connections.
For information on RPI and how it affects the actual packet interval (API), see
the EtherNet/IP Performance Application Solution,
ENET-AP001 .
Select a Communication
Format
When you configure an I/O module, you select a communication format for
the module. 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
The available communication formats depend on the type of I/O module. In
general:
See online help in RSLogix 5000 programming software for specific
communication formats per I/O module.
If you have this type of I/O module And want Select a communication format that specifies
Digital Module rack-optimized connection Rack Optimization
Scheduled Data...
Input Data
Output Data
Digital Module a direct connection Any connection that is not Rack Optimization
to use specialty features of the
module, such as diagnostics,
timestamps, or electronic fuses Full Diagnostics...
CST Timestamped...
Analog Module a direct connection
(only direct connection is
supported for analog modules)
Float Data...
Integer Data
CST Timestamped...