Rockwell Automation 2098 CompactLogix Indexing Motion Accelerator Toolkit Quick Start - Manual (Page 60)

60 Publication IASIMP-QS011B-EN-P — January 2009
Chapter 5 Motion Logix Integration
9. Repeat step 4…step 8 for each additional axis.
The result might look like this.
Set the Axis k Constant
The CompactLogix Indexing Motion application file (CIMLxx_xaxis_v00x.acd) allows you to
program all motion instructions in user units (inches or degrees, for example) instead of encoder
counts. You will need to set the conversion factor (or k constant) from user units to encoder
counts to allow the drive to be commanded properly. Follow these steps to set the k constant for
each axis in your RSLogix 5000 program.
1. In RSLogix 5000 software, expand the
Explorer window to gain access to the
controller tags.
Double-click Controller Tags.
2. Make sure the Monitor Tags tab is in
front.
3. Locate and expand the tag for each axis in your system. You may have renamed them from
their original AXIS_0x name.
The third tag element in the list for each axis is the name.SET_CountsPerUnit tag. This is
where the k constant is entered.
4. If needed, consult the documentation for your
mechanical system components and your servo
motor to calculate your k constant. Enter the
number of encoder counts per desired user unit
in the space provided.
All values entered in your Logix motion
instructions will now be scaled by this value.
IMPORTANT
Please note this scaling effect when entering your desired speeds, positions, and acceleration
rates in your motion instructions.