Rockwell Automation 1746-HSRV SLC Servo Control Module User Manual - Manual (Page 102)

Publication 1746-6.1.2 - July 2000
Setting Up Your SLC Servo Module 7-23
For example, the current value for time to maximum speed is 0.2
seconds. From the above motion test, the % acceleration ramp selected
is 22%.
14. Enter the new time to accelerate to maximum speed in
configuration file F8 (words 30-31).
15. Set the SLC Servo Module in Estop.
16. Toggle the bit (word 0, bit 15) to download this configuration.
17. Reset Estop.
Determining Velocity and
Acceleration Feedforward The following information for determining velocity and acceleration
feedforward is for Velocity Feedforward (VFF) only.
Speed calibration and axis acceleration are critical for proper velocity
feedforward operation.
Velocity Feedforward
With velocity feedforward, you add a percentage of the computed
velocity command to the position error velocity command. Velocity
feedforward can reduce the following error at constant axis speed to
near zero. But at values above 70%, velocity feedforward can
introduce a small overshoot at the end of a transition. Select a value
acceptable for the application.
Acceleration Feedforward
With acceleration feedforward, you add a percentage of the computed
acceleration command to the position error velocity command.
Acceleration feedforward only affects the axis following error on a
velocity transition. We use this percentage along with high values of
velocity feedforward. Select a value acceptable for the application.
Calculate: To equal:
Time to Maximum
Speed (new value) (1.05 seconds x 0.2) divided by 0.22
0.96 seconds