User manual

110 Publication LOGIX-AP010B-EN-P - May 2010
Chapter 6 Communication and Networking
Choosing a ControlNet Network or EtherNet/IP Network for
communication between controllers will depend on the requirements of each
particular application.
Use the NetLinx Selection Guide, publication NETS-SG001
to determine
which network is the best fit for your application.
In converting from an S5 LAN with multiple controllers to a Logix network,
the possibility of performing all the required control functions in a central rack
that connects to remote I/O racks via ControlNet, EtherNet/IP and/or
DeviceNet should be considered.
The Logix controllers have larger memory capacity than the older S5 CPUs so
it is possible that software code previously distributed over several controllers
could now be executed by one Logix controller or multiple controllers located
in a central chassis.
The cabling for an S5 LAN network consisted of a dedicated 4-core cable that
had a maximum length between two LAN nodes defined by the cable and bus
terminal used.
Logix controllers can communicate over an Ethernet network by using network
switches to connect over a wider area with greater speed and reliability.
The SINEC L1 LAN operates at a baud rate of 9.6 Kbps compared to Logix
EtherNet cards that can operate at speeds of 10/100 Mbps.
Remote I/O can be connected to a centralized controller by using ControlNet
communication modules or remote communication modules.
Logix uses the following ControlNet bridge modules to interface a ControlNet
network to a Logix backplane:
• 1756-CN2
• 1756-CNB
The Logix system provides redundant media for ControlNet networks.
Redundancy requires no additional programming and is transparent to any
devices connected over a ControlNet network. Redundant networks use the
following ControlNet bridge modules:
• 1756-CN2R
• 1756-CNBR
NetLinx networks use connections to establish communication between two
devices. The number of connections allowed depends on the type of modules
and the type of connections that are established.