ABB ACS580 Series, Firmware Manual, Page: 102 / 462

98 Program features
The function is also available for scalar motor control with a frequency reference. The
input of the function is shown by
28.96 Frequency ref act 7 .
Example
A fan has vibrations in the range of 540…690 rpm and 1380…1560 rpm. To make the
drive avoid these speed ranges,
• the critical speeds function by turning on bit 0 of parameter 22.51 Critical speed
function , and
• set the critical speed ranges as in the figure below.
Settings
• Critical speeds: parameters 22.51 … 22.57 (page 210 )
• Critical frequencies: parameters 28.51 … 28.57 (page 233 ).

User load curve
The User load curve provides a supervisory function that monitors an input signal as
a function of frequency or speed, and load. It shows the status of the monitored signal
and can give a warning or fault based on the violation of a user defined profile.
The user load curve consists of an overload and an underload curve, or just one of
them. Each curve is formed by five points that represent the monitored signal as a
function of frequency or speed.
In the example below, the user load curve is constructed from the motor nominal
torque to which a 10% margin is added and subtracted. The margin curves define a
540
690
1380
1560
1 Par. 22.52 = 540 rpm
2 Par. 22.53 = 690 rpm
3 Par. 22.54 = 1380 rpm
4 Par. 22.55 = 1560 rpm
1 2 3 4
22.01 Speed ref unlimited (rpm)
(output of function)
22.87 Speed reference act 7 (rpm)
(input of function)
ACS580 FW.book Page 98 Wednesday, September 21, 2016 9:48 PM