Siemens SINAMICS S120 Function Manual page 111

When DSC is activated, it is recommended to use a new setting for the position controller
gain KPC in the master.
When DSC is activated, neither channels p1155 and p1160 for the position setpoint values
nor the channel for the extended setpoint value are used.
Value p1430 for the speed pre-control is taken into account.
Deactivating
If both KPC = 0 (p1191=0) and XERR = 0 (p1190 = 0) are set, the DSC structure is dissolved
and the "DSC" function is deactivated. In this case, only the value from p1430 from speed
pre-control is taken into account.
Since it is possible to set higher gain factors using DSC, the control loop can become
unstable when DSC is disabled. For this reason, before deactivating DSC, the value for KPC
in the master must be reduced.
Speed setpoint filter
A speed setpoint filter for smoothing the speed setpoint steps is not required when DSC is
active.
When the "DSC" function is used, speed setpoint filter 1 is only recommended for supporting
the position controller (e.g. to suppress resonance effects).
External encoder systems (except motor encoder)
If, with DSC active, an external encoder is to be used, this requires the selection of a
telegram with additional encoder actual values: Telegrams 06, 106, 116, and 118 or free
telegrams.
For optimum control in DSC mode, the same encoders must be used for the controller
(Master) and the drive via the parameter p1192 "DSC encoder selection".
Since the motor encoder is no longer used in this case, the adaptation factor for the
conversion of the selected encoder system into the motor encoder system is determined
using parameter p1193 "DCS encoder adaptation factor". The factor represents the ratio of
the pulse difference between the motor encoder and the used encoder for the same
reference distance.
The effect of the parameters p1192 and p1193 is illustrated in function diagram 3090.
Diagnostics
Via the parameter r1407.4 = 1 it can be indicated whether the speed setpoint of DSC is
used.
Preconditions for the indication:
● p1190 and p1191 must be connected to a signal source with a value of > 0
● OFF1, OFF3 und HALT2 must not be active.
● The motor data identification must not be active.
● Master control must not be active.
Drive functions
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
(DSC structure activated).
Servo control
3.15 Dynamic Servo Control (DSC)
111