Allen-Bradley ControlLogix - How the Controllogix System Uses Connections; What this Appendix Contains; Appendix A

1756-6.5.3 - December 1999
Appendix A
Allocating Communication Connections
What This Appendix Contains
This appendix describes how to determine the connection requirements for
a ControlLogix system.
How the ControlLogix System
Uses Connections
The ControlLogix system uses a connection to establish a communication
link between two devices. This includes Logix5550 controllers,
communication modules, input/output modules, produced/consumed tags,
and messages. Connections take many forms:
• Logix5550 controller direct to local I/O or local communication module
• Logix5550 controller direct to remote I/O or remote communication
module
• Logix5550 controller to remote chassis (rack optimized)
• produced and consumed tags
• messaging, including block-transfers
You indirectly determine the number of connections that the Logix5550
controller requires by configuring the controller to communicate with other
devices in the system.
Each module in the ControlLogix system supports a limited number of
active connections. Take these connection limits into account when
designing your system.
For information about See page
How the ControlLogix system uses connections A-1
Determining I/O connection requirements A-2
Determining connections for produced and
consumed tags
A-6
Determining connections for messaging A-8
Determining total connection requirements A-9