32 Rockwell Automation Publication 5094-UM001E-EN-P - April 2020
Chapter 1 Digital I/O Module Operation in a Logix 5000 Control System
Connection Over an 
EtherNet/IP Network
During module configuration, you must configure the Connection over 
EtherNet/IP parameter. The configuration choice dictates how input data is 
broadcast over the network.
The FLEX 5000 I/O modules use one of the following methods to broadcast 
data:
• Multicast - Data is sent to all network devices
• Unicast - Data is sent to a specific controller depending on the module 
configuration
Unicast is the default setting. We recommend that you use Unicast because 
it reduces network bandwidth usage.
Input Module Operation
Logix 5000 controllers do not poll the FLEX 5000 input modules for input data. 
Instead, the input modules send data at the RPI.
FLEX 5000 input modules reside in a FLEX 5000 I/O system that is accessible 
to a Logix 5000 controller over an EtherNet/IP network. A FLEX 5000 
EtherNet/IP adapter is the first component in a FLEX 5000 I/O system and 
connects the system to the EtherNet/IP network.
FLEX 5000 input modules communicate input data to the FLEX 5000 
EtherNet/IP adapter at the defined RPI. The input data consists of point and 
status data.
At the RPI, the following events occur.
1. The digital input module scans its points for input data.
2. The module sends the data to the FLEX 5000 EtherNet/IP adapter.
3. The FLEX 5000 EtherNet/IP adapter in the FLEX 5000 I/O system 
sends the data over the EtherNet/IP network.
4. One of the following:
• If the controller is directly connected to the EtherNet/IP network, it 
receives the input data immediately.
• If the controller is connected to the EtherNet/IP network through 
another communication module, the module sends the data to its 
backplane and the controller receives it.