Introduction
Add an extended DIO network if you have existing distributed equipment—which you may not want to reconfigure—to the M580 device network. An extended DIO network is a physical and logical part of the Ethernet RIO network.
An extended DIO network is an Ethernet-based network containing distributed equipment on a copper wire that runs from a single port connection. If you use dual-port equipment that supports RSTP, you can connect the equipment in a daisy chain loop to the device network ports on the BMENOC0301/BMENOC0311 Ethernet communication module.
Considerations:
There is an Ethernet backplane connection to the device network.
A BMENOC0301/BMENOC0311 module communicates with a BMENOC0321 control network module on the local rack to support communication with the M580 control network. The Ethernet backplane ports on these modules are enabled so that the extended DIO network communicates with the CPU and the device network through the backplane.
Example
This graphic shows an extended DIO network. The BMENOC0301/BMENOC0311 module communicates with the BMENOC0321 module on the local rack. The Ethernet backplane ports of both modules are enabled so that the extended DIO network communicates with both the device network and the control network:

1 The M580 CPU connects RIO drops and distributed equipment to the main ring.
2 A BMENOC0301/BMENOC0311 Ethernet communication module on the local rack is connected to the independent DIO network.
3 A BMENOC0321 control network module on the local rack connects an independent DIO network to the M580 control network. This module also provides transparency between the device network and the control network.
4 A BMENOS0300 network option switch module on an RIO drop connects a DIO sub-ring to the main ring.
5 A BMENOS0300 network option switch module on an RIO drop connects a DIO cloud to the main ring.