Rockwell Automation 20-750-ENETR PowerFlexDual-Port EtherNet/IP Option Module - Manual (Page 99)

Rockwell Automation Publication 750COM-UM008A-EN-P - July 2012 99
Chapter
6
Using Explicit Messaging (Adapter mode only)
This chapter provides information and examples that explain how to use Explicit
Messaging with a ControlLogix controller to configure and monitor the option
module and connected PowerFlex 750-Series drive.
For explicit messaging with a PLC-5, SLC 500, or MicroLogix 1100/1400
controller, see Controller Examples for EtherNet/IP Network Communications
with PowerFlex 750-Series Drives, publication 750COM-AT001.
See Chapter 5 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 slave device’s
parameters on the network.
Topic Page
About Explicit Messaging 99
Performing Explicit Messaging 100
ControlLogix Controller Examples 101
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 Nonvolatile 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.
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 dialog box 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.