Allen-Bradley 1756-CNB/E, User Manual

Page: 148 / 186

Publication 1756-UM523F-EN-P - December 2006
148 Set Up EtherNet/IP Communication Across Subnets
Keep an HMI
Communicating with the
Primary Chassis
If you are not using IP swapping, your HMIs must direct their
communication to the new primary chassis after a switchover.
ControlLogix Redundancy Alias Topic Switcher software can most
easily do this. Look for this software on the CD along with your
firmware.
The ControlLogix Redundancy Alias Topic Switcher software works
with RSLinx alias topics. Together they keep your HMI communicating
with the primary controller after a switchover.
HMI Communication
IMPORTANT
To use the ControlLogix Redundancy Alias Topic Switcher
software, your computer needs an activation file for RSLinx
software. The activation file lets you perform DDE/OPC
communication.
E
N
B L
5
5
Chassis A
E
N
B L
5
5
Chassis B
Topic for Chassis A Topic for Chassis B
Alias Topic
012345
Xxxx Xx
RSLinx
Software
HMI tags – In your HMI project, each tag references an
alias topic in RSLinx software. This lets RSLinx software
redirect communications to the appropriate chassis.
Alias topic – In RSLinx software, an alias topic
represents a flexible communication path to one of
several controllers (topics).
•
In a ControlLogix redundancy system, the alias topic
points to the topic for the primary controller.
•
When a switchover occurs, the alias topic points to
the topic for the new primary controller.
Topic – In RSLinx software, a topic represents a
specific path to a controller. Since each ENBT
and EWEB module uses a unique IP address,
create a topic for the controller in each
redundant chassis.
ControlLogix Redundancy Alias Topic Switcher software
– Automatically reads a value in RSLinx software to
determine which controller is primary. It then commands
the alias topic to switch to the topic for that controller.