Technology Function: Friction Characteristic - Siemens SINAMICS S120 Function Manual

7.14

Technology function: friction characteristic

The friction characteristic curve is used to compensate the friction torque for the motor and
the driven machine. A friction characteristic enables the speed controller to be precontrolled
and improves the response.
Ten interpolation points are used for each friction characteristic curve. The coordinates of
every interpolation point are defined by a speed parameter (p382x) and a torque parameter
(p383x) (point 1 = p3820 and p3830).
Features
● Ten interpolation points are available for mapping the friction characteristic curve.
● An automatic function allows you to record the friction characteristic curve (record friction
● A connector output (r3841) can be applied as friction torque (p1569).
● The friction characteristic can be activated and deactivated (p3842).
Commissioning via parameters
In p382x, speeds for the measurement are predefined as a function of the maximum speed
p1082 during first commissioning. They can be changed appropriately.
The automatic friction characteristic plot can be activated using p3845. The characteristic is
then plotted the next time that it is enabled.
The following settings are possible:
● p3845 = 0 Friction characteristic curve recording deactivated
● p3845 = 1 Friction characteristic curve recording activated, all directions of rotation
● p3845 = 2 Friction characteristic curve recording activated, positive direction of rotation
● p3845 = 3 Friction characteristic curve recording activated, negative direction of rotation
Dangerous motor motion while plotting the friction characteristic
When the friction characteristic is plotted, the drive can cause the motor to move. As a
result, the motor may reach maximum speed.
The Emergency Off functions must be fully operational during commissioning. To protect
the machines and personnel, the relevant safety regulations must be observed.
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
characteristic curve).
The friction characteristic curve is recorded in both directions of rotation. The results of
the positive and negative measurement are averaged and entered in p383x.
WARNING
7.14 Technology function: friction characteristic
Basic functions
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