
Rockwell Automation Publication 520COM-UM004A-EN-E - November 2013 49
Using Acyclic Messaging Chapter 6
Acyclic Messaging for DPV1
Class
The 25-COMM-P adapter provides the following PROFIBUS DPV1 Class 1
Acyclic Services:
• READ – This service is used to read a parameter in the PowerFlex 520-
series drive or the adapter.
• WRITE – This service is used to write a parameter in the PowerFlex 520-
series drive or the adapter.
Acyclic Messaging Examples
Examples of using PROFIBUS DPV1 Class 1, Acyclic Messaging to read and
write a Host (drive) parameter is described in this section.
Read Example for Host Parameter 1 [Output Freq]
To read the PowerFlex 520-series drive parameter 1 [Output Freq] using a
Class 1 Acyclic Read Service, setup a CompactLogix controller (with a MVI69-
PDPMV1 PROFIBUS Master). After the master is setup, the CompactLogix
tags must be populated with the values to read the parameter as shown in Class 1
Acyclic Read for Host Parameter 1 [Output Freq] on page 50.
Host parameter 1 [Output Freq]:
• Slot Number = 0x00 + Quotient of (1/256) + 1 = 1
• Index Number = Remainder of (1/256) = 1
• Length in bytes of the value of the parameter (16-bit integer value) / 8 = 2
To test the Read service, you may manually enter the values as shown below into
the MVI69-PDPMV1 controller scoped tags, where a ProSoft MVI69-
PDPMV1 PROFIBUS master module is installed in the backplane of the
CompactLogix controller rack.
• MVI69PDPMV1.Mailbox.Class1AcyclicRead.Out.SlotNumber = 1
• MVI69PDPMV1.Mailbox.Class1AcyclicRead.Out.SlaveAddress = 3
• MVI69PDPMV1.Mailbox.Class1AcyclicRead.Out.Length = 2
• MVI69PDPMV1.Mailbox.Class1AcyclicRead.Out.Index = 1
Next, manually enter a value of ‘1’ into the
MVI69PDPMV1.MailboxCommand.Class1AcyclicRead tag to send the
message.
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