User manual

1 Publication CNET-UM001C-EN-P - November 2005
Appendix A
Connection Use Over ControlNet
Use This Appendix
ControlNet communication modules use connections to manage
communication. A connection is a point-to-point communication mechanism
that transfers data between a transmitter and a receiver.
ControlNet communication modules use connections that transfer data from a
Logix application running on one end-node to another device, such as a Logix
application or I/O, running on another end-node.
ControlNet Connections
Connections are allocations of resources that provide faster more reliable
communication between modules than unconnected messages. The
ControlNet communication modules and adapters support both direct and
rack-optimized connections to remote I/O adapters.
Connected messaging supports the following example functions:
• Logix controller message transfer to Logix controller
• I/O or produced/consumed tag
• Program upload
• RSLinx DDE/OPC client
• PanelView polling of Logix controller
There are four types of ControlNet connections:
Table A.1 ControlNet Connection Types
Read this
chapter for:
• 1756-CN2, 1756-CN2R modules
• 1756-CNB, 1756-CNBR modules
• 1769-L32C, 1769-L35CR controllers
• 1784-PCC, 1784-PCIC, 1784-PCICS,
1784-PKTCS cards
• 1788-CNx cards
• 1794-ACN15, -ACNR15 adapters
• 1797-ANCR adapter
Connection Type Description
Bridged A connection that passes through the ControlNet module. The end point of the connection could be an
I/O module, another ControlNet node, another controller or a device on a different network (bridged).
Example: a connection from a controller through a 1756-CNB and 1756-CNBR to another controller.
Rack-optimized A rack-optimized connection is a connection to a rack or assembly object in the ControlNet module.
Data from selected I/O modules is collected and produced on one connection (the rack-optimized
connection) rather than on a separate direct connection for each module.
Direct A connection from a controller to an specific I/O module (as opposed to a rack-optimized connection).
Produced/consumed tag A connection that allows multiple controllers to share tags. One controller produces the tag and one or
more controllers consume it.