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DYN2MS-02F-0116A17
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Acceleration / Deceleration Soft Start
In Speed Servo Mode, the
Max Acceleration
parameter in the servo drive can be used to soft start/stop the
servo motor. Since the speed command is sent as a rough step reference, it is often desirable to smooth
out the servo motor’s movement dynamics. Without soft start, the servo motor can accelerate/decelerate
too instantaneously. Soft start creates a smooth s-curve motion.
The relation to physical acceleration / deceleration time is measured as the rise time from 10% of the tar
-
get speed to 90% of the target speed.
Rise from 10% to 90% time = 59.98/(
Max Acceleration
)
2
seconds
Physical acceleration time = 1.2 * 59.98/(
Max Acceleration
)
2
seconds
4.2 Speed Servo Mode
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Torque Filter Constant
TrqCons is a first order low-pass filter used to smooth torque delivery in speed servo mode
which improves stability and accuracy of servo motor speed. The bigger value means wider
frequency range of that filter. That filter can be expressed as:
a / ( S + a), here a = 26*TrqCons ; if TrqCons = 100, then a = 2600.
The filter is used to make the torque sent to the servo torque loop more smooth especially
for the heavier load when bigger SpeedGain setting is used. If a very quick response servo
with small load is desirable, the bigger value or even the value 127 should be used to en
-
sure stability and fast dynamic follow.
The Torque Filter Constant parameter should only be used in speed servo mode. Leave this
parameter at “127” in position servo mode.
Rough Motion
Smooth Motion!
Max Acceleration
