Copley Controls Accelnet Plus BEL Series User Manual page 21

Accelnet & Stepnet Plus Panels User Guide
V L
ELOCITY OOP
The velocity loop uses these gains:
Gain
Vp - Velocity loop proportional
Vi - Velocity loop integral
V G
ELOCITY AINS
The Velocity Gains Shift feature adjusts the resolution of the units used to express Vp and Vi, providing more
precise tuning. If the non-scaled value of Vp or Vi is 64 or less, the Low Gains Shift option is available to
increase the gains adjustment resolution. (Such low values are likely to be called for when tuning a linear motor
with an encoder resolution finer than a micrometer.) If the non-scaled value of Vp or Vi is 24001 or higher, the
High Gains Shift option is available to decrease the gains adjustment resolution.
V L
ELOCITY OOP
The velocity loop contains four programmable digital filters. The input filter should be used to reduce the effects
of a noisy velocity command signal. The three output filters are used to reduce the excitation of any resonance
in the motion system.
Two filter types can be programmed: the Low-Pass and the Custom Bi-Quadratic. The Low-Pass filter class
includes the Single-Pole and the Two-Pole Butterworth filter types. The Custom Bi-Quadratic filter allows
advanced users to define their own filters incorporating two poles and two zeros.
For more information on the velocity loop filters, see the CME User Guide.
V L
ELOCITY OOP
The output of the velocity loop is Commanded Current which is the input to the current loop.
G
AINS
Description
The velocity error (the difference between the actual and the limited
commanded velocity) is multiplied by this gain. The primary effect of this
gain is to increase bandwidth (or decrease the step-response time) as the
gain is increased.
The integral of the velocity error is multiplied by this value. Integral gain
reduces the velocity error to zero over time. It controls the DC accuracy of
the loop, or the flatness of the top of a square wave signal. The error
integral is the accumulated sum of the velocity error value over time.
S
HIFT
C O
OMMAND AND UTPUT
O
UTPUTS
F
ILTERS
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