Rockwell Automation 25-COMM-E2P PowerFlex 25-COMM-E2P Dual-Port EtherNet/IP Adapter - Manual (Page 73)

Rockwell Automation Publication 520COM-UM003A-EN-E - June 2013 73
Chapter
6
Using Explicit Messaging
This chapter provides information and examples that explain how to use Explicit
Messaging to configure and monitor the adapter and connected
PowerFlex 520-series drive.
See Using the I/O on page 63 for information about the I/O Image, using Logic
Command/Status, Reference/Feedback, and Datalinks.
About Explicit Messaging Explicit Messaging is used to transfer data that does not require continuous
updates. With Explicit Messaging, you can configure and monitor a device’s
parameters on the network.
Topic Page
About Explicit Messaging 73
Performing Explicit Messaging 74
CompactLogix Controller Examples 74
ATTENTION: Risk of injury or equipment damage exists. The examples in this
publication are intended solely for purposes of example. There are many
variables and requirements with any application. Rockwell Automation, Inc.
does not assume responsibility or liability (to include intellectual property
liability) for actual use of the examples shown in this publication.
ATTENTION: Risk of equipment damage exists. If Explicit Messages are
programmed to write parameter data to Non-Volatile Storage (NVS) frequently,
the NVS will quickly exceed its life cycle and cause the drive to malfunction. Do
not create a program that frequently uses Explicit Messages to write parameter
data to NVS. Datalinks do not write to NVS and should be used for frequently
changed parameters.
ATTENTION: If you need to make frequent parameter changes using Explicit
Messages, set Host parameter C121 [Comm Write Mode] to 1 “RAM only”.
IMPORTANT When an explicit message is performed, by default no connection is made
since it is an “unconnected” message. When timing of the message transaction
is important, you can create a dedicated message connection between the
controller and drive by checking the “Connected” box on the Communications
tab message configuration screen during message setup. These message
connections are in addition to the I/O connection. However, the trade off for
more message connections is decreased network performance. If your
application cannot tolerate this, do not check the “Connected” box, which is
recommended.