Rockwell Automation Allen-Bradley DriveLogix 5730 User Manual page 144

7-10 Communicating with Devices on an ControlNet Link
This type of message:
CIP data table read or write
PLC2, PLC3, PLC5, or SLC (all types)
CIP generic
block-transfer read or write
(1)
You can connect CIP generic messages, but for most applications, we recommend you leave CIP generic messages unconnected.
MSG instruction to keep the connection open (cache) or to close it after
sending the message.
And this communication method:
CIP
CIP with Source ID
DH+
CIP
Connected messages are unscheduled connections on ControlNet.
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.
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 The connection closes after the MSG instruction is done. This frees up
connection that connection for other uses.
The following is from the 5720 manual and is a place holder. We need to put
real information here!
The controller has the following limits on the number of connections that
you can cache:
If you have this software
and firmware revision:
11.x or earlier
12.x or later
Then you can cache:
• block transfer messages for up to 16 connections
• other types of messages for up to 16 connections
up to 32 connections
Uses a connection:
X
X
(1)
Optional
X