Rockwell Automation 1756-RMxx ControlLogix Enhanced Redundancy System User Manual - Manual (Page 94)

94 Rockwell Automation Publication 1756-UM535D-EN-P - November 2012
Chapter 5 Configure the ControlNet Network
Keep these points in mind when you use produced and consumed connections
over a ControlNet network in an enhanced redundancy system:
• During a switchover, the connection for tags that are consumed from a
redundant controller can drop briefly.
– The data does not update.
– The logic acts on the last data that it received.
After the switchover, the connection is reestablished and the data begins to
update again.
• You cannot bridge produced and consumed tags over two networks. For
two controllers to share produced or consumed tags, both must be
attached to the same network.
• Produced and consumed tags use connections in both the controllers and
the communication modules being used.
• Because the use of produced and consumed tags uses connections, the
number of connections available for other tasks, such as the exchange of
I/O data, is reduced.
The number of connections available in a system depends on controller
type and network communication modules used. Closely track the
number of produced and consumed connections to leave as many as
necessary for other system tasks.