Rockwell Automation Logix5000 Controllers Produced and Consumed Tags Programming Manual - Manual (Page 10)

Chapter 1 Produce and Consume a Tag
This controller Can produce and consume tags over this network
Backplane ControlNet EtherNet/IP
1768 CompactLogix X
ControlLogix X X X
DriveLogix X X
SoftLogix5800 X X X
For two controllers to share produced or consumed tags, both controllers must be
attached to the same network, such as a ControlNet or Ethernet/IP network. You
cannot bridge produced and consumed tags over two networks.
Produced and consumed tags each require connections. As you increase the
number of controllers that can consume a produced tag, you also reduce the
number of connections the controller has available for other operations, like
communication and I/O.
Important: If a consumed-tag connection fails, all of the other tags being consumed from that remote
controller stop receiving new data.
Each produced or consumed tag uses the following connections.
This Type of Tag Uses This Many Connections
Produced tag number_of_consumers + 1
Consumed tag 1
Example: Connection Requirements of a Produced or Consumed Tag
•
A ControlLogix controller producing 4 tags for 1 controller uses 8 connections:
− Each tag uses 2 connections (1 consumer + 1 = 2).
− 2 connections per tag x 4 tags = 8 connections.
• Consuming 4 tags from a controller uses 4 connections (1 connection per tag x 4 tags = 4 connections).
As you organize your tags for produced or consumed data (shared data), follow
these guidelines.
Guideline Details
Create the tags at the controller scope. You can share only controller-scoped tags.
Use one of these data types:
•
DINT
• REAL
• Array of DINTs or REALs
• User-defined
To share other data types, create a user-defined data type that contains the required data.
Connection requirements of
a produced or consumed
tag
Organize tags for produced
or consumed data
10 Rockwell Automation Publication 1756-PM011F-EN-P - October 2014