User Load Curve - ABB ACS180 Firmware Manual

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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
working envelope for the motor so that excursions outside the envelope can be
supervised, timed and detected.
Motor torque / Nominal torque
1.2
1.0
0.8
0.6
0.4
0.2
1
0.0
-0.2
0
1 = Overload curve (five points)
2 = Nominal process load curve
3 = Underload curve (five points)
An overload warning and/or fault can be set to occur if the monitored signal stays
continuously over the overload curve for a defined time. An underload warning and/or
fault can be set to occur if the monitored signal stays continuously under the
underload for a defined time.
Overload can be for example used to monitor for a saw blade hitting a knot or fan
load profiles becoming too high.
Underload can be for example used to monitor for load dropping and breaking of
conveyer belts or fan belts.
2
3
10 20
Program features 63
30 40
Output frequency (Hz)
50