Siemens SINAMICS S120, Function Manual

Page: 170 / 1094

Servo control
4.16 Dynamic Servo Control (DSC)
Drive functions
170
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
Operating states
The following operating states are possible for DSC (for details, see function diagram 3090
in the SINAMICS S120/S150 List Manual):
Operating state for DSC Meaning
Speed/torque precontrol with linear
interpolation
As a result of the step-like torque precontrol in the position
controller cycle, a pulsed torque characteristic is obtained with
the excitation cycle.
Speed precontrol with splines
1)
•
The position setpoint is made symmetrical.
• The speed precontrol value is not made symmetrical.
Speed/torque precontrol with
splines 1)
• The position setpoint is made symmetrical.
•
The speed precontrol value is made symmetrical.
2)
• The torque precontrol value is not made symmetrical.
1)
The following improvements are obtained as a result of the spline interpolation:
- A finer interpolation of the torque in the speed controller cycle and so smoother movements and
the avoidance of the impact torques.
- Very high path accuracy for torque speed precontrol (i.e. smaller following error in the control be-
havior).
- High-frequency path movements are possible
2)
For active symmetrization (T_SYMM > 0), using p1427 you can set an additive symmetrizing time
constant T_SYMM_ADD to symmetrize the speed precontrol value when torque precontrol is ac-
tive.
In this case, the speed precontrol value is symmetrized with the sum of the following time con-
stants:
T_SYMM (see p1195) + T_SYMM_ADD (p1427) + 0.5 · T_speed_controller_cycle (p0115[1])
The speed generation is considered automatically using the position differences with a half speed
controller cycle.
Activation
If the preconditions for dynamic servo control are fulfilled, then the DSC structure is activated
using a logical interconnection of the following parameters via a selected PROFIdrive
telegram:
● p1190 "DSC position deviation XERR"
● p1191 "DSC position controller gain KPC"
● p1194 "CI: DSC control word DSC_STW"
● p1195 "CI: DSC symmetrizing time constant T_SYMM"
● p1430 "CI: Speed precontrol"