Introduction
An M580 local rack can contain one CPU and up to six communication modules, including a maximum of three BMENOC0301/BMENOC0311 Ethernet communication modulesand only one BMENOC0321 control network module. You can also use a maximum of three BMXNOM0200 Modbus communication modules.
This sample local rack shows a BMEP584040 CPU and four Ethernet communication modules:

1 M580 CPU with Ethernet I/O scanner service
2 BMENOC0301 Ethernet communication module with standard Web services
3 BMENOC0311 Ethernet communication module with FactoryCast Web services
The BMENOC0311 module has all the capability and functionality of the BMENOC0301, plus access to FactoryCast services. For more information about these modules, refer to the M580 BMENOC0301/11 Ethernet Communication Module Installation and Configuration Guide.
For further details about other types of modules you can install, refer to the local rack topic.
Maximum Number of Communication Modules on the Local Rack
This table shows the maximum number of communication modules you can install on the local rack, depending upon the CPU you choose:
CPU |
Maximum Number of Communication Modules(1) |
---|---|
BMEP581020 |
2 |
BMEP582020 |
2 |
BMEP582040 |
2 |
BMEP583020 |
3 |
BMEP583040 |
3 |
BMEP584020 |
4(2) |
BMEP584040 |
4(2) |
BMEP585040 |
6(2) |
BMEP586040 |
6(2) |
BMEH582040 |
2 |
BMEH584040 |
4(2) |
BMEH586040 |
6(2) |
1. This number includes BMENOC0301/11, BMENOS0300, BMXNOM0200 modules. 2. Only three of these modules can be BMENOC0301/BMENOC0311 modules. |
Interlinking a BMENOC0321 Module to the CPU
You cannot link the extended (service) port of a BMENOC0321 control network module to the embedded Ethernet port of the CPU in the local rack:

Using Multiple Local Racks for a Synchronization Network
You can use multiple local racks to create an isolated PAC synchronization network (using messaging or scanning on an isolated DIO network (each PAC managing its own device network and accessing a shared control network).
Each Ethernet local rack contains a CPU with Ethernet I/O scanning and a maximum of six Ethernet communication modules, only three of which can be BMENOC0301/BMENOC0311 modules.
The Ethernet backplane port of one of the BMENOC0301/BMENOC0311 modules is not enabled and connects to an isolated DIO network for the purpose of PAC synchronization.
If you have multiple PACs that share the same network, you can perform PAC synchronization through the BMENOC0321 control network module. However, if the PACs do not share the same network, perform PAC synchronization in this manner:

1 BMEP585040 CPU with Eternet I/O scanner service connecting to the device network
2 BMENOC0321 control network module connecting to the control network
3 BMENOC0301/BMENOC0311 Ethernet communication module connecting to the PAC control network
4 PC monitoring station on the control network