1.1.1 Direct coiler tension control (Mode 2)

The characteristics of the direct tension control are as follows:

The speed controller is operated as a PI-controller and over-modulated with a Dv. The limitation of the speed controller corresponds to the tension torque. The tension controller has a corrective effect on this limitation. The torque setpoint Tqset is computed from the tension torque TqT, the acceleration torque TqA, and the friction torque TqF (Tqset = TqT + TqA + TqF). The setpoint torque is set relative to the rated coiler torque Tqrtd.

With the indirect coiler tension control, the tension setpoint affects a special coiler tension controller.

The actual tension is injected at an analog input via a tension actual value sensor.

The coiler tension controller’s output affects as a supplement the torque setpoint Tqset and therefore the current limits (Lim[+]; Lim[-]) of the converter. In this case, the torque limits must be enabled with the “TQ_EN” signal, and the speed controller of the base unit must be over-modulated with the supplementary velocity DV. The maximum torque setpoint is specified via parameters.

The tension controller operates with a constant amplification factor. The limitation of the tension controller depends to thw tension setpoint. During stand still, tha gain of the tension controller is changed to a smaler value.
The tension controller output is interpreted as a DF and is converted with the radius to a tension torque.
   DMFW =  DF * r
The tension torque at the shaft must be related to the maximum torque of the motor; it is renormalized with the factor
   Fmax * rmax / (Mmot * i).

Independent of the current torque setpoint, you can limit to an internal programmable torque via the “TQ_RED” signal.

In case of an emergency stop, the internal maximum torque always takes effect, independent of the current torque setpoint.

1.1.2 Direct coiler tension control (Mode 3)

The characteristics of the direct coiler tension control are as follows:

Mode 2 with additional torque setpoint.