Siemens SINAMICS S120 Function Manual page 831

Operating principle
To maintain a constant tension of the continuous web, the drive torque is increased linearly
as the wound roll diameter increases - or is decreased linearly as the diameter decreases.
To protect the material being wound, the tension is reduced according to a characteristic as
the wound roll diameter increases.
The calculation of the continuously changing moment of inertia permits a torque precontrol
during a steady decrease or increase of the winder speed.
By using an encoder, a speed controlled operation of the winder is possible. The winder can
be operated without an encoder by controlling the tension torque, with two scaling
parameters p1552 and p1554 for tension torque limitation (see torque limitation).
Calculation of the moment of inertia for torque precontrol
The function diagram section below shows the calculation flow for servo control with encoder
[5042] / without encoder [5210]:
Figure 11-7
The following function diagram section shows the calculation flow for vector control [6031]:
Figure 11-8
Drive functions
Function Manual, (FH1), 01/2013, 6SL3097-4AB00-0BP3
dn/dt
r 1493
+
+
p 1497
1
Torque precontrol with servo control
dn/dt
Torque precontrol with vector control
r 1493
Applications
11.4 DCC axial winder
p 1497
1
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