Direction Reversal Without Changing The Setpoint - Siemens SINAMICS S120 Function Manual

7.9

Direction reversal without changing the setpoint

The direction of rotation of the motor can be reversed using the direction reversal via p1821
without having to change the motor rotating field by interchanging two phases at the motor
and having to invert the encoder signals using p0410.
The direction reversal via p1821 can be detected as a result of the motor direction of
rotation. The speed setpoint and actual value, torque setpoint and actual value and also the
relative position change remain unchanged.
The direction change can be identified as a result of the phase voltage (r0089). When the
direction reverses, then the absolute position reference is also lost.
In the vector control mode, in addition, the output direction of rotation of the drive converter
can be reversed using p1820. This means that the rotating field can be changed without
having to interchange the power connections. If an encoder is being used, the direction of
rotation must, when required, be adapted using p0410.
Note
Rotating/moving measurement for motor data identification of SERVO drives
Use parameter p1959[0...n].14/15 = 0 to activate a direction inhibit for the rotating
measurement for motor data identification where necessary. The direction inhibit should be
deactivated with p1959[0...n].14/15 = 1 for complete and accurate identification of the motor.
Features
● No change to the speed setpoint and actual value, the torque setpoint and actual value
● Only possible when the pulses are inhibited
NOTICE
Position reference is lost at direction reversal
If direction reversal is configured in the data set configurations (e.g. p1821[0] = 0 and
p1821[1] = 1), then when the function module "Basic positioner" or "Position control" is
activated, the absolute adjustment is reset each time the system boots or when the
direction changes (p2507), because the position reference is lost when the direction
reverses.
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
and the relative position change.
7.9 Direction reversal without changing the setpoint
Basic functions
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