Rockwell Automation 20-750-PBUS Profibus DPV1 Option Module - Manual (Page 62)

62 Rockwell Automation Publication 750COM-UM004B-EN-P - September 2012
Chapter 6 Acyclic Messaging
Figure 13 - Acyclic Class 1 Read Response Data using RSLogix Ladder Logic
Write Example for Drive Parameter 520 - [Max Fwd Speed]
To write to the PowerFlex 750-Series drive parameter 520 - [Max Fwd Speed]
using a Class 1 Acyclic Write Service, setup a ControlLogix controller (with a
MVI56-PDPMV1 Profibus Master). After the master is setup, the ControlLogix
tags must be populated with the correct slot and index addressing values to write
the parameter as shown in
Figure 14 .
Drive Parameter 520 - [Max Fwd Speed]:
• Slot No. = 0x00 + Quotient of (520 / 256) + 1 = 3
• Index No. = Remainder of (520 / 256) = 8
• Length in bytes of the value of the Parameter (32 bit floating point value) /
8 = 4
To test the Write Service, you may manually enter the values as shown below into
the MVI56-PDPMV1 controller scoped tags where a ProSoft MVI56-PDPMV1
Profibus master module has been installed in the backplane of the ControlLogix
controller rack.
• MVI56PDPMV1.Mailbox.AcyclicWrite.Out.SlotNumber = 3
• MVI56PDPMV1.Mailbox.AcyclicWrite.Out.SlaveAddress = 3
• MVI56PDPMV1.Mailbox.AcyclicWrite.Out.Length = 4
• MVI56PDPMV1.Mailbox.AcyclicWrite.Out.Index = 8
The data bytes to be written can be entered in the
MVI56PDPMV1.Mailbox.AcyclicWrite.Out.Data[] array, or the data may be