Specifications

Appendix A 41
Time
Velocity
Anti-Resonance or
Active Damping
(above 3 rps)
Electronic Viscosity
(below 3 rps)
3 rps 3 rps
Above 3 rps, the ZETA6104 automatically enables either anti-resonance or active damping—
but not both at the same time. They are mutually exclusive.
If active damping is set to zero (DACTDPØ), the ZETA6104 enables anti-resonance. If the
DACTDP command is set to any setting other than zero, the ZETA6104 enables active
damping. This relationship is shown in the next drawing.
Drawing shows factory default settings:
 •Anti-Resonance enabled ( DAREN1)
 •Active Damping disabled ( DACTDPØ)
ZETA6104 – Internal Circuitry
Motor
Current Command
Current
Command
Modulator
Power
Amplifier
Motor
Terminal
Voltages
Anti-
Resonance
(DACTDPØ)
Active
Damping
(DACTDP1-15)
Scaling for Motor Parameters:
•Static Torque ( DMTSTT command)
•Inductance ( DMTIND command)
Anti-Resonance
Enable: DAREN1
Disable: DARENØ
Scaling for
System Inertia
(DACTDP command)
Dynamic Error Modulates
Current Command
(above 3 rps only)
1
2
14
15
0
Notice in the drawing that anti-resonance can also be disabled with a command (DARENØ).
Differences between anti-resonance and active damping are described next; refer to the block
diagram above.
Anti-Resonance Anti-resonance monitors the ZETA6104’s motor terminals, and looks at power exchange
between the ZETA6104 and motor. From this, it extracts information about error in rotor
position caused by resonance or ringing. It modifies the internal motor current command to
correct for the error.
Anti-resonance is a general-purpose circuit. It corrects rotor position error, without knowledge
about the system—whether the motor is large or small, or the system inertia is high or low.
You cannot modify the circuit’s gains, or customize it for a particular application—but, anti-
resonance is easy to use. When enabled via the DAREN1 command, it works automatically.