Siemens SINAMICS S120, Function Manual

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Servo control
4.2 Setpoint addition
Drive functions
88
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
4.2 Setpoint addition
Definition
Setpoint addition allows up to 2 speed setpoints to be combined. While main and
supplementary setpoints used in the setpoint channel are influenced by speed limits and the
ramp-function generator, the speed setpoint is directly active here. As a consequence, up
ramps and down ramps of a ramp-function generator are eliminated.
Speed actual values of a higher-level position control are suitable as source, which can be
entered using a PROFIdrive telegram. Interconnect the telegram control word as BICO
source. The speed setpoint is then refreshed in the bus cycle, e.g. in the PROFINET cycle.
A supplementary speed setpoint can, through setpoint addition, minimize disturbing
influences on the speed setpoint from the position control.
Figure 4-1 Setpoint addition
Interpolator
When using a speed setpoint from a higher-level control system, the speed setpoints are
only refreshed (updated) in the bus cycle. The bus cycle is normally significantly slower than
the current controller cycle of the SINAMICS drive, which can result in steps. When using an
interpolator, the speed setpoint is linearly interpolated between the bus cycles, so that steps
that possibly occur can be eliminated.
The interpolator is only active when the "Basic positioner" function module is activated - or
isochronous PROFIdrive operation is active.
Parameterizing setpoint addition
1. Interconnect the signal source for p1155.
2. Interconnect the signal source for p1160.
3. To activate the interpolator for the speed setpoint, in the drop-down list for 1189[1] select
"yes".