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6F3A4768
5.5.2 Torque Control
In winding machines, the winding materials are controlled at a specified tension. Therefore, the host PLC
calculates the torque (reference) to be output from the motor. Additionally, the drive unit controls to output a
torque corresponding to this torque reference. Furthermore, operation is made with speed control when the
winding is completed or winding of next materials is started.
On the other hand, if operation based on the torque reference sent from the host PLC continues in case of a fault,
such as material breakage, overspeed may result. In such case, the control is automatically changed to the
speed control. (Torque control with speed limit function)
When using this torque control, set $FLG_TENSEL to “1”.
The following describes how to use the torque control for operation with normal rotation and positive torque.
Normal rotation and
positive torque
a) Winding (tension control and normal winding) b) After winding (speed control)
Reverse rotation and negative torque
c) Winding (reverse winding)
Fig. 5.5.2 Tension Control
(1) Speed control
To operate with speed control, the speed reference corresponding to the line speed is input in the same
manner as described for normal operation.
When the EXT sequence signal is turned on and ST sequence signal is turned off, the speed control is
started.
(2) Torque control (with speed limit function)
As the operation preparation completed (READY) and operation command (EXT) signals are on, the torque
control selection (ST) signal is turned on. After that, the TRQ_REF signal is compared with the external
torque reference TENS_R1 signal. External torque reference TENS_R1, whichever is smaller, is detected
by the logic that picks up the minimum value, and then used as the torque reference T_R signal.
When performing the torque control with the speed limit function, the speed reference signal, which is
approximately 5% higher than the line speed, is input from the host PLC. As a result, the speed reference
5% higher than the actual speed is input and the TRQ_REF single showing the speed control calculation
result is saturated by the positive torque limit value. The external torque reference is then used for control.
(If operation is made with the external torque reference, the motor is actually operated at a speed
equivalent to the line speed. As the speed reference is increased 5%, the speed deviation always becomes
positive, causing the speed control calculation result to increase to the limit value.)
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