Siemens SINAMICS S120 Function Manual page 170

Servo control
4.16 Dynamic Servo Control (DSC)
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
Speed/torque precontrol with linear
interpolation
Speed precontrol with splines
Speed/torque precontrol with
splines
The following improvements are obtained as a result of the spline interpolation:
1)
- 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
For active symmetrization (T_SYMM > 0), using p1427 you can set an additive symmetrizing time
2)
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"
170
1)
1)
Meaning
As a result of the step-like torque precontrol in the position
controller cycle, a pulsed torque characteristic is obtained with
the excitation cycle.
The position setpoint is made symmetrical.
•
The speed precontrol value is not made symmetrical.
•
The position setpoint is made symmetrical.
•
The speed precontrol value is made symmetrical.
•
The torque precontrol value is not made symmetrical.
•
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
2)
Drive functions