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Rockwell Automation 1756-IF4FXOF2F ControlLogix High-speed Analog I/O Module User Manual

Page 141

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Rockwell Automation Publication 1756-UM005B-EN-P - January 2013

141

Module Operation in a Remote Chassis

Appendix E

Configure High-speed
Analog I/O Modules in a
Remote Chassis

ControlLogix ControlNet interface modules (catalog numbers 1756-CNB or
1756-CNBR) are required to communicate with a ControlLogix high-speed
analog I/O module in a remote chassis. You must configure the communication
module in the local chassis and the remote chassis before adding new high-speed
analog I/O modules.

1.

Configure a communication module for the local chassis.

This module handles communication between the controller’s local chassis
and the remote chassis. Add a 1756-CNB or 1756-CNBR module to the
local chassis using the steps on

page 73

.

2.

Configure a communication module for the remote chassis.

3.

Choose a 1756-CNB or 1756-CNBR module and configure it.

You can now configure remote I/O modules by adding them to the remote
communication module. Follow the same procedures as explained earlier in this
chapter for configuring local I/O modules.

IMPORTANT

Although a high-speed analog I/O module works in a remote chassis, it reaches
maximum data production rates only in the local chassis.

For example, if use a ControlLogix high-speed analog I/O module in a local
chassis, the minimum RPI rate =

300 μs. However, when the module is used

in a remote chassis connected by ControlNet, you must account for the NUT. The
minimum ControlNet NUT = 2 ms. In this case, the fastest time to receive data
from a high-speed analog I/O module is doubled when compared to a local
chassis.

IMPORTANT

Be aware of the two communication format choices available for 1756-CNB
modules. For more information on the differences between Rack Optimization
and Listen-only Rack Optimization, see the ControlLogix Digital I/O Modules
User Manual, publication

1756-UM058

.

Right-click the 1756-CNB

module in the local chassis.

Choose New Module.