Speed Controller Autotune - ABB ACS880 Firmware Manual

44 Program features
The function is also available for scalar motor control with a frequency reference. The
input of the function is shown by
Frequency ref unlimited.
Example
A fan has vibrations in the range of 540 to 690 rpm and 1380 to 1560 rpm. To make
the drive avoid these speed ranges,
• enable the critical speeds function by turning on bit 0 of parameter
speed function, and
• set the critical speed ranges as in the figure below.
22.01 Speed ref unlimited
(output of function)
1560
1380
690
540
Settings
• Critical speeds: parameters
• Critical frequencies: parameters


Speed controller autotune

The speed controller of the drive can be automatically adjusted using the autotune
function. Autotuning is based on an estimation of the mechanical time constant
(inertia) of the motor and machine.
The autotune routine will run the motor through a series of acceleration/deceleration
cycles, the number of which can be adjusted by parameter
times. Higher values will produce more accurate results, especially if the difference
between initial and maximum speeds is small.
The maximum torque reference used during autotuning will be the initial torque (ie.
torque when the routine is activated) plus
by the maximum torque limit (parameter group
(99 Motor data). The calculated maximum speed during the routine is the initial speed
(ie. speed when the routine is activated) +
by 30.12 Maximum speed
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28.96 Frequency ref act
(rpm)
22.87 Speed reference act 7
1 2 3 4
(input of function)
22.51...22.57
28.51...28.57
or 99.09 Motor nominal
7, the output by
1 Par. 22.52
2 Par. 22.53
3 Par. 22.54
4 Par. 22.55
(page 215)
(page 251).
25.40 Autotune repeat
25.38 Autotune torque
30 Limits) or the nominal motor torque
25.39 Autotune speed
speed.
28.97
22.51 Critical
= 540 rpm
= 690 rpm
= 1380 rpm
= 1560 rpm
(rpm)
step, unless limited
step, unless limited