Rockwell Automation 5730 DriveLogix5730 Controller for PowerFlex 700S Drives with Phase II Control - Manual (Page 123)

Communicating with Devices on an EtherNet/IP Link 6-19
Sending Messages
The DriveLogix5730 controller can send MSG instructions to other
controllers and devices over an EtherNet/IP link. Each MSG instruction
requires you to specify a target and an address within the target.
Important: Revision 15.xx of DriveLogix firmware adds more stringent
range checks when reading to or writing from tags. Message
packets are limited to 240 bytes. This could cause some MSG
instructions that worked in previous firmware revisions to not
work in revision 15.xx firmware. For example, use a CIP
Generic MSG instruction to perform a Get Attribute Single
service. The attribute is 4 bytes in length. Assume the
destination tag is an INT data type (2 bytes in length). In
revision 13.xx firmware, the MSG instruction places the first 2
bytes of the attribute in the destination tag. In revision 15.xx
firmware, the MSG instruction errors because the destination
tag is not large enough. To correct this error, change the
destination tag to a DINT data type.
MSG instructions are unscheduled. The type of MSG determines whether or
not it requires a connection. If the MSG instruction requires a connection, it
opens the needed connection when it is executed. You can configure the
MSG instruction to keep the connection open (cache) or to close it after
sending the message.
The update time of local I/O modules may increase when the controller is
bridging messages.
Important: Bridging over the DriveLogix5730 controller should be
targeted toward applications that are not real time dependent,
such as RSLogix 5000 program downloads and ControlFlash
updates.
This type of MSG:
Using this communication
method: Uses a
connection: Which you
can cache:
CIP data table read or write CIP X X
PLC-2, PLC-3, PLC-5, or SLC
(all types) CIP X X
CIP with Source ID X X
DH+ X
CIP generic CIP X
(1)
X
block-transfer read or write na X X
(1)
You can connect CIP generic messages, but for most applications, we recommend you leave CIP generic messages unconnected.