User guide

➃ Servo Tuning 31
Drive Tuning Procedure (Velocity Drives Only)
The Drive Tuning Procedure leads you through the following steps:
➀ Launch and set up Motion Architect's Drive Tuner module.
➁ Tune the drive to output the desired velocity at a given voltage from the 6250.
➂ Tune the drive (iteratively) to achieve the desired response.
NOTE
Be sure to complete the Tuning Setup Procedure before proceeding with the following drive
tuning procedure. Unlike the Tuning Setup Procedure , you must tune one axis at a time.
Step 1 Launch and set up Motion Architect's Drive Tuner Module:
To effectively tune the drive, you should use Motion Architect's interactive Drive Tuner
module (this is available only if you have the Servo Tuner option for Motion
Architect, part number 95-013714-01). It greatly improves your efficiency and gives
you powerful graphical tools to measure the performance of the drive. The rest of this tuning
procedure is based primarily on using the Drive Tuner module.
a. Launch Motion Architect.
b. Under the Product pull-down menu, choose Selection, select the 6250 and click
Okay.
c. Under the Utilities pull-down menu, choose Drive Tuner.
d. Under the Communication pull-down menu, choose Connect to initiate the RS-232C
link with the 6250 over the COM port. The drive shutdown and fault lights should be
green; if not, press the Drive On button (if that does not work, check the shutdown
output connection to the drive).
e. Under the Setup pull-down menu, set the appropriate drive fault output level and the
encoder resolution values.
f. Click on the Step button in the Data Acquisition display. In the dialog box, select
the voltage and duration for the step profile to be used in the iterative tuning process in
Step 3 below.
g. Click on the Sampling button in the Data Acquisition display. In the dialog box,
select the data sampling period and frequency of samples for Motion Architect's data
gathering function to be used in Step 3 below.
Step 2 Tune the drive to output the desired velocity at a given voltage from the 6250:
a. If your system has mechanical stops, manually move the load to a position mid-way
between them.
b. Using your mouse or using the arrow keys, move the slide bar in the Drive Command
Voltage
display to select a voltage of 10.0 volts. Adjust the drive gain factor (sometimes
called the tach gain) such that when the 6250's command output is 10V, the drive's velocity
just reaches its maximum value. Refer to your drive's user documentation if necessary.
EXAMPLE
Suppose your drive can run at a max. velocity of 7000 rpm (or 116.67 rps). If the drive
gain factor is 20 rps/V, then the drive will reach the maximum velocity (116.67 rps) when
the 6250's command output is only 5.833V. This means the full range of ±10V is not fully
usable. To use the full range of ±10V, the gain factor has to be adjusted to 11.667 rps/V.
Drive manufactures usually provide a potentiometer for adjusting this gain factor. Some
manufacturers provide a few preset values selectable with jumpers or DIP switches.
c. Using your mouse or using the arrow keys, move the slide bar in the Drive Command
Voltage
display to select a voltage of 1.0 volts. The motor should start moving; note the
value displayed in the Velocity data field. (If you are not using Motion Architect, enter
the SOFFS1 command.)
d. Click on the Step button. In the Drive Gain data field (1V = ___ units/sec), enter the
value displayed in the Velocity data field from Step 2.b. above.
e. After you have established the proper velocity-for-voltage setting, set the commanded
voltage back to zero (see Step 2.b.).