Velocity Mode; Tuning - Aerotech BA-SineDrive Series User Manual

Modes of Operation and Tuning

4.2.2. Velocity Mode

To operate the BAS in velocity mode, the user must first change the operating mode to
velocity command. This can be done by changing PRM:20 to 2. For this change to take
effect, a reset (CTRL-D) must be sent to the BAS.
When operating in velocity mode, the BAS relies on an external controller to close the
position loop. The BAS, utilizing a proportional gain (PRM:1) and an integral gain
(PRM:2), closes the velocity loop digitally and sinusoidally commutates a brushless
motor. PRM:3 can be used as an electronic tach to scale the velocity.
Offsets in the velocity loop can be removed by modifying PRM:12.
4.3.
Starting with a zero input command signal (P1-17, P1-18 tied to sig. common), apply
power to the amplifier. If the motor spins uncontrollably, remove power and switch the
polarity of the input. If an encoder is being used, switch the sine and cosine input signals.
Verify complement signals (sin & sin-N, cos & cos-N) are of correct phasing.
Again, apply power to the amplifier. If the motor begins to oscillate, reduce Kp and KI
until oscillation stops. The Kp and Ks gains can be adjusted to provide maximum stiffness
on the motor shaft.
The PRM:12 is used to cancel any bias in the internal or external control circuit that
would cause the motor to rotate when the input command signal is zero.
4-2
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Tuning

Aerotech, Inc.
BA SineDrive User's Manual
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Version 1.4