Rockwell Automation 1794-OB16D FLEX I/O Diagnostic Modules User Manual - Manual (Page 60)

Publication 1794-UM061A-EN-P - July 2006
58 Configure Your Adapter and Digital Modules on a ControlNet Network
Set Up the Hardware
In this example, the Logix5000 controller uses a ControlNet communication
module in the local chassis to connect to the ControlNet network. The
distributed (remote) I/O has a ControlNet adapter to connect it to the
ControlNet network.
Make sure:
• all wiring and cabling is properly connected
• the communication driver [such as, AB-PCIC(S)-1] is configured for the
programming workstation
Setting a Requested
Packet Interval (RPI)
When you configure an I/O module, you define the RPI for the module. The
RPI specifies the period at which data updates over a connection. For example,
an input module sends data to a controller at the RPI that you assign to the
module. Configure the RPI in milliseconds.
RPIs are only used for modules that produce or consume data. For example a
local ControlNet 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 asynchronously
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 determines the
number of packets per second on a connection. Each I/O module has a limit
of how many packets it can handle per second. If you exceed this limit, the
module cannot open any more connections.
Local Chassis
Logix5000 controller
with ControlNet
communication module Distributed I/O
ControlNet adapter
with I/O modules
Data
Programming
Terminal
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