User Manual

108 Rockwell Automation Publication 750COM-UM008A-EN-P - July 2012
Chapter 6 Using Explicit Messaging (Adapter mode only)
ControlLogix Controller Example Ladder Logic Program to Write
Multiple Parameters
A Scattered Write message is used to write to multiple parameters. This write
message example writes the following values to these five 32-bit REAL (floating
point) parameters in a PowerFlex 750-Series drive:
See DPI Parameter Object
on page 163 (Class code 0x93) or Host DPI
Parameter Object on page 177 (Class code 0x9F) for parameter numbering.
Table 9 - Example Controller Tags to Write Multiple Parameters
Figure 32 - Example Ladder Logic to Write Multiple Parameters
PowerFlex 750-Series Drive Parameter Write Value
536 - [Accel Time 2] 11.1 Sec
538 - [Decel Time 2] 22.2 Sec
575 - [Preset Speed 5] 33.3 Hz
576 - [Preset Speed 6] 44.4 Hz
577 - [Preset Speed 7] 55.5 Hz
Operand Controller Tags for Scattered Write Message Data Type
XIC Execute_Scattered_Write_Message BOOL
MSG Scattered_Write_Message MESSAGE
IMPORTANT
If the explicit message scattered write must be written continuously, then use
a separate explicit message single write for each parameter using DPI
Parameter Object Class code 0x93 and attribute A (see page 104
). Attribute A
writes to RAM—not NVS (EEPROM) memory. This example scattered write
message using attribute 0 writes to NVS. Over time, continuous writes will
exceed the EEPROM life cycle and cause the drive to malfunction.