Rockwell Automation 1756-HYD02 ControlLogix Hydraulic Servo Module - Manual (Page 56)

56 Publication 1756-UM525A-EN-P - June 2003
Chapter 4 Using the 1756-HYD02 Module Features
Units Tab
Use the Units tab to determine the programming and configuration units used
to define your motion axis. When RSLogix 5000 software is online and the
controller transitions to hard run, or the axis loop is on (i.e., active), then all
the attributes on this tab transition to a read only state. When any attribute
transitions to a read only state, then any pending attribute changes are
reverted.
The table below lists the configurable features available on the Units tab.
Feature: Definition:
Position Units User-defined engineering units (rather than feedback counts) used to label all motion-related values (e.g.,
position or velocity) These position units can be different for each axis.
Position Units should be chosen for maximum ease of use in your application. For example, linear axes
might use position units of inches or meters whereas rotary axes might use units of revolutions or degrees.
Average Velocity Timebase Specifies the time (in seconds) to be used to calculate the average velocity of the axis. This value is
computed by taking the total distance the axis travels in the amount of time specified, and dividing this
value by the timebase.
The average velocity timebase value should be large enough to filter out the small changes in velocity that
would result in a "noisy" velocity value, but small enough to track significant changes in axis velocity. A
value of 0.25 to 0.50 seconds should work well for most applications.