Rockwell Automation 20-750-PBUS Profibus DPV1 Option Module - Manual (Page 57)

Rockwell Automation Publication 750COM-UM004B-EN-P - September 2012 57
Chapter
6
Acyclic Messaging
This chapter provides information and examples that explain how to use Profibus
Class 1 DPV1 Acyclic Messaging to configure and monitor the PowerFlex 750-
Series drive through the 20-750-PBUS option module.
About Acyclic Messaging Acyclic messaging is used to transfer data to the PowerFlex 750-Series drive
through the 20-750-PBUS option module and other connected peripherals that
do not require continuous updates. Acyclic messaging, or DPV1 messaging in the
case of the 20-750-PBUS option module, is also used to configure and monitor a
drive's parameters on a Profibus network. Drive parameters as well as peripheral
Host and Device parameters can be accessed via acyclic messaging for a PowerFlex
750-Series drive. For a full list of drive parameters, see the PowerFlex 750-Series
AC Drives Programming Manual, publication
750-PM001 , and for a list of 20-
750-PBUS option module Host and Device Parameters, see Appendix B . To use
acyclic messaging read and write services, you need the values of the slot and
index to which a parameter is associated. Value ranges for slot and index are
shown in
Table 5 .
Topic Page
About Acyclic Messaging 57
Acyclic Messaging for DPV1 Class 1 60
Example Messaging 60
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 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 Acyclic 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 Acyclic
Messages to write parameter data to NVS. Datalinks do not write to NVS
and should be used for frequently changed parameters.