Rockwell Automation 5720 DriveLogix System - Manual (Page 45)

Publication 20D-UM002C-EN-P - November 2003
What Is DriveLogix? 2-11
DriveLogix controllers can produce and consume tags over:
• a ControlNet network
• an EtherNet/IP network.
The total number of tags that can be produced or consumed is limited by the
number of available connections and memory. If the controller uses all of its
connections for I/O and communication devices, no connections are left for
produced and consumed tags.
Determining Connections
for Messages Messages transfer data to other devices, such as other controllers or operator
interfaces. Connected messages can leave the connection open (cache) or close
the connection when the message is done transmitting. The following table
shows which messages use a connection:
Connected messages are unscheduled connections on both ControlNet and
EtherNet/IP networks.
If a MSG instruction uses a connection, you have the option to leave the
connection open (cache) or close the connection when the message is done
transmitting.
IMPORTANT
For two controllers to share produced or consumed
tags, both controllers must be attached to the same
control network (such as a ControlNet or Ethernet/IP
network). You cannot bridge produced and
consumed tags over two networks.
This type of message: And this communication method: Uses a connection:
CIP data table read or write X
PLC2, PLC3, PLC5, or SLC (all types) CIP
CIP with Source ID
DH+ X
CIP generic CIP
Optional
(1)
block-transfer read or write X
(1) You can connect CIP generic messages, but for most applications, we recommend you leave CIP generic messages unconnected.
If you: Then:
Cache the connection The connection stays open after the MSG instruction is done.
This optimizes execution time. Opening a connection each time
the message executes increases execution time.
Do not cache the
connection The connection closes after the MSG instruction is done. This
frees up that connection for other uses.