Rockwell Automation 1756-RMxx ControlLogix Enhanced Redundancy System User Manual - Manual (Page 97)

Rockwell Automation Publication 1756-UM535D-EN-P - November 2012 97
Configure the ControlNet Network Chapter 5
Use a Scheduled or
Unscheduled Network
It is up to the user to decided between using a scheduled or unscheduled
network.
Use a Scheduled Network
Schedule or reschedule your ControlNet network when you are executing
these tasks:
• Commissioning a new redundant system.
• Adding a new chassis of remote ControlLogix I/O that is set to use the
Rack Optimized communication format.
• Adding any remote I/O besides ControlLogix I/O. For example, if adding
FLEX I/O modules, you must schedule the network.
• Using produced/consumed data. Any time you add a produced/consumed
data tag, you must reschedule the ControlNet network.
To schedule or reschedule your ControlNet network, you put your redundant
system in Program mode.
Use an Unscheduled Network
You can use an unscheduled network when you are doing the following:
• Adding a new remote I/O chassis of ControlLogix I/O that does not use
the Rack Optimized communication format. That is, direct connections
to the I/O are used.
• Adding a ControlLogix I/O module to a chassis that has already been
scheduled and uses the Rack Optimized communication format.
• Adding some drives that support adding I/O while online.
• Using ControlNet to monitor HMI or the controller program.
You can add those components to the unscheduled network while your
redundant system is online and in Run mode. We recommend that you do not
use an unscheduled network for all of your I/O connections.
The use of 1756-CN2/B, 1756-CN2R/B, and 1756-CN2RXT modules
provides increased capacity for adding I/O while online compared to 1756-CNB
or 1756-CNBR modules. With this increased capacity, you can easily add I/O
and increase ControlNet connections used without affecting your redundant
system performance.