Def / Type
FbEq 16b / 32b
DescriptionName / Range /
Selection
No.
Enables/disables (or selects a source that
enables/disables) speed error window control, sometimes
also referred to as deadband control or strip break
protection. It forms a speed supervision function for a
torque-controlled drive, preventing the motor from running
away if the material that is being held under tension breaks.
Note: Speed error window control is only effective when
the Add operating mode is active (see parameters 19.12
and 19.14), or when the drive is a speed-controlled follower
(see page 36).
In normal operation, window control keeps the speed
controller input at zero so the drive stays in torque control.
If the motor load is lost, then the motor speed will rise as
the torque controller tries to maintain torque. The speed
error (speed reference - actual speed) will increase until it
exits the speed error window. When this is detected, the
exceeding part of the error value is connected to the speed
controller. The speed controller produces a reference term
relative to the input and gain (25.2 Speed proportional gain)
which the torque selector adds to the torque reference.
The result is used as the internal torque reference for the
drive.
The activation of speed error window control is indicated
by bit 3 of 6.19 Speed control status word.
The window boundaries are defined by 24.43 Speed error
window high and 24.44 Speed error window low as follows:
Reference + [24.44] rpm
Reference
Reference - [24.43] rpm
Reference + [24.43] rpm
Reference
Reference - [24.44] rpm
Speed error
window
Speed error
window
Forward
Reverse
0 rpm
Speed (rpm)
Parameters 283
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