Allen-Bradley ControlNet Compact GuardLogix 1769, User Manual, Page: 73 / 100

Produce and Consume Tags (interlock controllers) Chapter 5
Make sure of the following:
•
The ControlNet communication modules are connected to a scheduled
•
ControlNet network.
•
All wiring and cabling are properly connected.
The communication driver is configured for the programming
workstation.
TIP
If you are sharing tags only between ControlLogix controllers, the
controllers are not controlling any I/O modules. You can set the
communication format of the 1756-CN2, 1756-CN2R, 1756-CNB, or
1756-CNBR modules in the remote chassis to None. This limits
connection usage and network traffic.
Determine Connections for
Produced and Consumed
Tags
Logix controllers can produce (broadcast) and consume (receive) system-shared
tags that are sent and received via the ControlNet communication module. Each
produced and consumed tag requires connections.
Table 17 - Tag Type and Connections
Tag Type Required Connections
Produced The produced tag requires two connections. The producing controller must have
one connection for the produced tag and the first consumer and one connection
for each additional consumer (heartbeat). The heartbeat is a small scheduled
packet the consumer sends to indicate that it is getting the produced data.
As you increase the number of controllers that can consume a produced tag, you
also reduce the number of available controller connections for other operations,
such as communication and I/O.
Consumed
Each consumed tag requires one connection for the controller that is consuming
the tag.
All ControlNet modules support at least 32 connections. The number of
available connections limits the number of tags that can be produced or
consumed. If the communication module uses all of its connections for I/O and
other communication modules, no connections are left for produced and
consumed tags.
Rockwell Automation Publication CNET- UM001E-EN-P - June 2016
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