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

6.7

Direction reversal without changing the setpoint

Features
● Not change to the speed setpoint and actual value, the torque setpoint and actual value
● Only possible when the pulses are inhibited
Note
If one of the options p1959.14/15: Positive/negative direction of rotation permitted is selected
in parameter p1959 in conjunction with rotational direction parameter p1821, the effects on
the rotation of direction are as follows:
Positive direction of rotation (p1959.14 =1) with setting p1821= 0 or 1 respectively means:
Clockwise or counter-clockwise direction respectively.
Negative direction of rotation (p1959.15 =1) with setting p1821= 1 or 0 respectively means:
Counter-clockwise or clockwise direction respectively.
Description
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.
Overview of important parameters (see SINAMICS S120/S150 List Manual)
● r0069 Phase current, actual value
● r0089 Actual phase voltage
● p1820 Direction of rotation reversal of the output phases (vector)
● p1821 Rotational direction
● p1959[0...n] Rotating measurement configuration
● p2507 LR absolute encoder adjustment status
Drive functions
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
and the relative position change.
CAUTION
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), as the position reference is lost when the direction reverses.
6.7 Direction reversal without changing the setpoint
Basic functions
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