32
6250 Servo Controller User Guide
S t e p 3
Tune the drive (iteratively) to achieve the desired response:
a.
In the
Data Acquisition
display, select the
Start
button to trigger the short move and
the data collection function.
If you are not using Motion Architect:
Enter the following commands to create and execute a step velocity command:
Co mma n d
De s c r i p t i o n
>
DEF STEPOUT
Begin definition of the program called
STEPOUT
-
SGPØ,Ø
Set the SGP gain to zero
-
SGIØ,Ø
Set the SGI gain to zero
-
SGVØ,Ø
Set the SGV gain to zero
-
SGAFØ,Ø
Set the SGAF gain to zero
-
SGVFØ,Ø
Set the SGVF gain to zero
-
SMPERØ,Ø
Disable checking the maximum allowable position error
-
SOFFSØ.5
Set the command output to 0.5 volts
-
T1
Wait for 1 second
-
SOFFSØ
Set the command output to zero volts (stopping the motor)
-
SMPER4ØØØ,4ØØØ
Re-enable checking the maximum allowable position error
-
END
End definition of the program called
STEPOUT
>
STEPOUT
Execute the program called
STEPOUT
(the motor will move
for 1 second and then stop)
b .
Observe the plot of the commanded velocity versus the actual velocity in the
Captured
Velocity
graph (or on the oscilloscope).
Using the tuning methods specified in the drive's user documentation, tune the drive to
achieve a first-order response (no overshoot) as illustrated below—repeat Steps 3.a. and
3.b. as necessary.
Commanded Velocity
Actual Velocity
Velocity
Time
S t e p 4
Proceed to the Controller Tuning Procedure section to tune the 6250.
Motion Architect Automatic Gain Selection Feature
The drive scale factor and step response information gathered in the latest Drive Tuner
module session can be used in the Controller Tuner module to automatically select gains that
should greatly shorten the iterative nature of the controller tuning process. Use of this
feature is discussed in the
Controller Tuning Procedure.
Controller Tuning Procedure
The Controller Tuning Procedure leads you through the following steps:
➀
Launch Motion Architect's Controller Tuner module to tune the 6250.
➁
Select the 6250's servo Sampling Frequency Ratios (
SSFR
).
➂
Set up Motion Architect's data gathering functions.
➃
Optimize the Proportional (
SGP
) and Velocity (
SGV
) gains.
An alternative would be to use Motion Architect's Automatic Gain Selection feature, which
automatically calculates
SGP
and
SGV
gains (and
SGI
, if so desired) based on the last drive tuning
session.
➄
Use the Integral Feedback Gain (
SGI
) to reduce steady state error.
➅
Use the Velocity Feedforward Gain (
SGVF
) to reduce position error at constant velocity.
➆
Use the Acceleration Feedforward Gain (
SGAF
) to reduce position error during acceleration and
deceleration.
