Rockwell Automation 20-COMM-Q ControlNet Adapter - Manual (Page 85)

Using the I/O 5-11
20-COMM-C/Q ControlNet Adapter User Manual
Publication 20COMM-UM003F-EN-P
PowerFlex Digital DC Drives
The Reference/Feedback value is:
25000 = Maximum Reference Speed
The maximum Reference speed is set using drive parameter 45 - [Max Ref
Speed].
Using Datalinks A Datalink is a mechanism used by PowerFlex drives to transfer data to and
from the controller. Datalinks allow a drive parameter value to be read or
written without using an Explicit Message. When enabled, each Datalink
occupies two 16-bit or 32-bit words in both the input and output image. Use
adapter Parameter 08 - [Datalink Size] to determine whether the drive
uses 16-bit or 32-bit words for Datalinks.
Rules for Using Datalinks
• Each set of Datalink parameters in a PowerFlex drive can be used by
only one adapter. If more than one adapter is connected to a single drive,
multiple adapters cannot use the same Datalink.
• Parameter settings in the drive determine the data passed through the
Datalink mechanism. See the documentation for your drive.
• When you use a Datalink to change a value, the value is not written to
the Nonvolatile Storage (NVS) memory. The value is stored in volatile
memory and lost when the drive loses power. Thus, use Datalinks when
you need to change a value of a parameter frequently.
Datalink Scaling
PowerFlex 70/700/700H Drives and PowerFlex 700L Drives with 700 Control
When using RSLogix 5000 software, version 16.00 or later, Datalink
scaling is done automatically. However, when using RSLogix 5000
software, version 15.00 or earlier—or when using a PLC-5 or SLC 500
controller—Datalink scaling is not automatic and uses whole numbers
(INTs or DINTs). See the drive documentation to determine the unit
resolution for the associated parameter Datalink. For example, PowerFlex
700VC drive parameter 3 - [Output Current] has a 0.1 unit resolution.
Because Datalink scaling uses whole numbers, the Output Current value is
multiplied by 10 in the adapter and then sent over the network. Suppose the
actual Output Current value is 35.5 amps. Reading the associated parameter
Datalink received by the controller, the value would be 355. By using ladder
logic, divide the value by 10 in the controller to get the correct scaling. See
the drive documentation to determine if the Datalink parameter is a 16-bit or
32-bit parameter.