Operand Summary - Using The Auxiliary Encoder; Motion Smoothing; Using The It And Vt Commands (S Curve Profiling) - Galil Motion Control DMC-1000 User Manual

Table of Contents

OPERAND

_CEx

_DEx

_DVx

_GRx

_TDx

Motion Smoothing

The DMC-1000 controller allows the smoothing of the velocity profile to reduce the mechanical

vibration of the system.

Trapezoidal velocity profiles have acceleration rates which change abruptly from zero to maximum

value. The discontinuous acceleration results in jerk which causes vibration. The smoothing of the

acceleration profile leads to a continuous acceleration profile and reduces the mechanical shock and

vibration.

When operating with servo motors, motion smoothing can be accomplished with the IT and VT

command. These commands filter the acceleration and deceleration functions to produce a smooth

velocity profile. The resulting velocity profile, known as S curve, has continuous acceleration and

results in reduced mechanical vibrations.

The smoothing function is specified by the following commands:

IT x,y,z,w

VT n

The command, IT, is used for smoothing independent moves of the type JG, PR, PA and the

command, VT, is used to smooth vector moves of the type VM and LM.

The smoothing parameters, x,y,z,w and n are numbers between 0 and 1 and determine the degree of

filtering. The maximum value of 1 implies no filtering, resulting in trapezoidal velocity profiles.

Smaller values of the smoothing parameters imply heavier filtering and smoother moves.

The following example illustrates the effect of smoothing. Fig. 6.6 shows the trapezoidal velocity

profile and the modified acceleration and velocity.

Note that the smoothing process results in longer motion time.

PR 20000

AC 100000

DC 100000

76 • Chapter 6 Programming Motion

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Set gear ratio for gearing - the auxiliary encoder input can be used for gearing

Tell dual (auxiliary) encoder input position.