Allen-Bradley ControlLogix - Page 178

1756-6.5.3 - December 1999
A-4 Allocating Communication Connections
In this example, the owner controller communicates with all the digital I/O
in the remote chassis but uses only one connection. The data from all three
modules is sent together simultaneously at a rate specified by the
1756-CNB connection. This option eliminates the need for the three
separate connections shown in the previous example.
The local controller in this example uses these bidirectional connections:
The rack optimized connection conserves ControlNet connections and
bandwidth, but it limits the status and diagnostic information that is
available from the I/O modules.
Using a Rack Optimized Connection with I/O in a Remote Chassis
Local chassis Remote chassis
I
N
P
U
T
I
N
P
U
T
O
U
T
P
U
T
Rack optimized
connection for all I/O
ControlNet
41021
I
N
P
U
T
O
U
T
P
U
T
Owner Logix 5550
ControlNet
ControlNet
Interface module
Interface ModuleController
Connection Type Module Quantity Connections
per Module
Total
Connections
Logix5550 controller to local I/O module 2 1 2
Logix5550 controller to remote 1756-CNB module 1 1 1
total
3