Allen-Bradley ControlLogix Reference Manual

CIP Axis Attributes
Chapter 4
Rockwell Automation Publication MOTION-RM003I-EN-P - February 2018 385
The Position Units string attribute allows user-defined engineering units rather
than "counts" to be used for measuring and programming all motion-related values
(position, velocity, acceleration, etc). Position Units can be different for each axis
and should be chosen for maximum ease of use in the machine application. For
example, linear axes might use Position Units of "Inches", "Meters", or "mm" while
rotary axes might use Position Units of "Revs" or "Degrees".
The Position Units attribute can support an ASCII text string of up to 32
characters. This string is used by Logix Designer application in the axis
configuration dialogs to request values for motion-related parameters in the
specified Position Units. In this case, the software limits the maximum string
length to 15 characters.
Average Velocity Timebase
Usage Access Data
Type
Default Min Max Semantics of Values
Required - All Set/ SSV# REAL 0.25
0.001
(1 coarse
update
period)
32 (1000
coarse
update
period)
Sec
# Indicates the attribute cannot be set while the tracking command (Tracking Command bit in CIP Axis Status is true).
This attribute determines the period of time over which the system computes
Average Velocity for this axis instance.
Range limits based on coarse update period and history array size are ultimately
enforced for Average Velocity Timebase attribute by clamping to limit rather than
generating a value out of range error. Only if the value is outside the fixed
Min/Max limits is an out of range error given.
Conversion Constant
Usage Access Data
Type
Default Min Max Semantics of Values
Required - All
Set/
SSV#
REAL
Default Motion
Resolution
10
-12
10
12
Counts/Position Unit
# Indicates the attribute cannot be set while the tracking command (Tracking Command bit in CIP Axis Status is true).
This attribute is used as a scaling factor allowing axis position, velocity, and
acceleration attributes to be displayed or configured in the user's preferred units
specified by the Position Unit string attribute. Specifically, the Conversion
Constant, is used by the motion system to scale the axis position units into motion
planner counts and vice versa. The Conversion Constant represents the number of
counts of the motion planner per Position Unit.

Allen-Bradley ControlLogix Specifications

General

Brand	Allen-Bradley
Model	ControlLogix
Category	Industrial Electrical
Language	English