Rockwell Automation 1756-HYD02 ControlLogix Hydraulic Servo Module - Manual (Page 68)

68 Publication 1756-UM525A-EN-P - June 2003
Chapter 4 Using the 1756-HYD02 Module Features
Output Tab
Use the Output tab for offline configuration of the following:
• Scaling values that are used to generate gains.
• The analog loop’s low-pass digital output filter.
The parameters on this tab can be edited in two ways:
• Type parameter changes in the fields available on this tab and use the
OK or Apply buttons to save your edits.
• Edit in the Manual Adjust dialog. To do so:
a. Click on the Manual Tune button.
b. Use the spin controls to edit parameter settings.
Your changes are saved the moment a spin control changes any
parameter value.
The parameters on this tab become read-only when the controller is online if
the controller is set to Hard Run mode, or if a Feedback On condition exists.
When RSLogix 5000 is offline, the following parameters can be edited and the
program saved to disk using either the Save command or by clicking on the
Apply button. You must download the edited program to the controller before
it can be run.
The table below lists the configurable features available on the Output tab.
Feature: Definition:
Velocity Scaling Converts the output of the position loop into equivalent voltage to an external hydraulic axis. This
conversion “normalizes” the units of the position loop gain parameters so that variations in feedback
resolution, drive scaling, or mechanical gear ratios do not affect their values. The automatic loop tuning
procedures typically establish the Velocity Scaling value, but these values can be calculated, if necessary,
using the following guidelines.
Velocity Scaling = 100% / (Speed @ 100%)
For example, if this axis is using position units of inches, and the hydraulic system is designed such that
with an input of 100% (e.g. 10 Volts) the axis goes 55.6 inches per second, the Velocity Scaling attribute
value would be calculated as:
Velocity Scaling = 100% / (55.6) = 1.8% / Inches Per Second