Using FLEX I/O with a CompactLogix and ControlNet requires two separate actions.
1. The FLEX I/O connections are configured in RSLogix 5000 software, by adding FLEX I/O adapters and modules to the 'I/O Tree' section and configuring the Node Numbers and the Requested Packet Interval (RPI) values for each connection. This configuration is part of the program that is downloaded to the CompactLogix controller.
2. The ControlNet network segment is scheduled using RSNetworx for ControlNet software. When you "go online" with a ControlNet network and enter Edit mode, RSNetworx software reads the requested connections from the CompactLogix and calculates a ControlNet schedule based on those requested connections and the basic Network Properties you configure.
When you perform a "Save" function while in Edit Mode, the ControlNet network is scheduled and the schedule is saved to all of the ControlNet nodes.
ControlNet can be complicated, but you need to understand at least those two basic steps before continuing.