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Limits of indirect tension control:
If the torque required for turning the empty winding mandrel is 15% higher than the torque required
for developing the minimum tension (at D
min
), a method with direct tension control should be pre-
ferred.
The speed control range of the winder drive should not exceed 1:100. This means that with a winding
ratio D
max
/ D
min
= 10, the ratio of minimum and maximum production speed should not exceed VL
max
/ VL
min
= 10.
For the tension in the web, no direct benchmark is available.
The Diameter Calculator and compensation blocks (Speed Setpoint, Tension Setpoint,
Torque Setpoint) must be adjusted very carefully to obtain the required result.
NOTE
If torque control is to be used, extreme care must be taken to ensure that the working range is al-
ways above the current impression range, i.e. the motor speed in sensor-less configurations is high-
er than the speed set in Parameter
Frequency Limit
624
.
4.2
Example: Dancer control
By changing the dancer position, the circumferential speed of the winding spool is to be adjusted to
the winding material feed rate.
By applying a force on the dancer arm, the tensile force on the web can be controlled at the same
time.
If the material is fed without tension build-up of the winder, you don't have to use the Diameter Cal-
culator and the Electronic Gear. However, both function blocks can also be used in this case as a pilot
control in order to reduce the positioning tasks of the dancer controller.
The arrangement described above also enables direct tension control. In this case, the feedback from
a tension measuring device is used for tension control. For optimum results, all pilot control options
should be used in this case.
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ACU
Winding Drive
23
4.3
Example: Unwinding at constant speed
The unwinding speed is to be kept at a given speed. If a diameter sensor is available, this can simply
be realized as follows:
24
ACU
Wickelanwendungen
11/13