ABB ACS880 Firmware Manual page 39

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
28.96 Frequency ref act
(rpm)
1 2 3 4
22.51...22.57
28.51...28.57
7, the output by
1 Par. 22.52
2 Par. 22.53
3 Par. 22.54
4 Par. 22.55
22.87 Speed reference act 7
(input of function)
(page 161)
(page 186).
Program features 39
28.97
22.51 Critical
= 540 rpm
= 690 rpm
= 1380 rpm
= 1560 rpm
(rpm)