ABB ACSM1 Series, Manual

Page: 149 / 510

Parameters and firmware blocks
149
22
Firmware block:
SPEED FEEDBACK
(22)
Block outputs located in other
parameter groups 1.01 SPEED ACT (page 91 )
22.01 SPEED FB SEL FW block: SPEED FEEDBACK (see above)
Selects the speed feedback value used in control.
(0) Estimated Calculated speed estimate.
(1) Enc1 speed Actual speed measured with encoder 1. The encoder is selected by
parameter
90.01 ENCODER 1 SEL .
(2) Enc2 speed Actual speed measured with encoder 2. The encoder is selected by
parameter
90.02 ENCODER 2 SEL .
22.02 SPEED ACT FTIME FW block: SPEED FEEDBACK (see above)
Defines the time constant of the actual speed filter, ie, time within the actual speed has reached 63%
of the nominal speed (filtered speed =
1.01 SPEED ACT ).
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
mech
= ( n
nom
/ T
nom
) × J
tot
× 2 π / 60, where
J
tot
= total inertia of the load and motor (the gear ratio between the load and motor must be taken into
account)
n
nom
= motor nominal speed
T
nom
= motor nominal torque
To get a fast dynamic torque or speed response with a speed feedback value other than (0) Estimated
(see parameter 22.01 SPEED FB SEL ), the actual speed filter time must be set to zero.
See also parameter 26.06 SPD ERR FTIME .
0…10000 ms Time constant for actual speed filter.
SPEED FEEDBACK
5
TLF8 250 μsec (2)
22.01 SPEED FB SEL
[ Estimated ]
22.02 SPEED ACT FTIME
[ 3.000 ms ]
22.03 MOTOR GEAR MUL
[ 1 ]
22.04 MOTOR GEAR DIV
[ 1 ]
22.05 ZERO SPEED LIMIT
[ 30.00 rpm ]
22.06 ZERO SPEED DELAY
[ 0 ms ]
22.07 ABOVE SPEED LIM
[ 0 rpm ]
22.08 SPEED TRIPMARGIN
[ 500.0 rpm ]
22.09 SPEED FB FAULT
[ Fault ]
1.01 SPEED ACT