Speed Feedback - ABB ACSM1 Firmware Manual

22
Firmware block:

SPEED FEEDBACK

(22)
Block outputs located in other
parameter groups
22.01 SPEED FB SEL
Selects the speed feedback value used in control.
(0) Estimated
(1) Enc1 speed
(2) Enc2 speed
22.02 SPEED ACT FTIME
Defines the time constant of the actual speed filter, ie, time within the actual speed has reached 63%
of the nominal speed (filtered speed =
If the used speed reference remains constant, the possible interferences in the speed measurement
can be filtered with the actual speed filter. Reducing the ripple with filter may cause speed controller
tuning problems. A long filter time constant and fast acceleration time contradict one another. A very
long filter time results in unstable control.
If there are substantial interferences in the speed measurement, the filter time constant should be
proportional to the total inertia of the load and motor, in this case 10...30% of the mechanical time
constant
t = (n / T
mech nom nom
J = total inertia of the load and motor (the gear ratio between the load and motor must be taken into
tot
account)
n = motor nominal speed
nom
T = motor nominal torque
nom
To get a fast dynamic torque or speed response with a speed feedback value other than
(see parameter 22.01 SPEED FB
See also parameter
0...10000 ms
1.01 SPEED ACT
FW block: SPEED FEEDBACK
Calculated speed estimate.
Actual speed measured with encoder 1. The encoder is selected by
parameter 90.01 ENCODER 1
Actual speed measured with encoder 2. The encoder is selected by
parameter 90.02 ENCODER 2
FW block: SPEED FEEDBACK
1.01 SPEED
) × J × 2π / 60, where
tot
SEL), the actual speed filter time must be set to zero.
26.06 SPD ERR FTIME.
Time constant for actual speed filter.
SPEED FEEDBACK
(page 65)
(see above)
SEL.
SEL.
(see above)
ACT).
Parameters and firmware blocks
117
(0) Estimated