Dynamic Feedforward Control (Following Error Compensation); General Information - Siemens SINUMERIK 840D sl Function Manual

5.5

Dynamic feedforward control (following error compensation)

5.5.1

General information

Axial following errors
The axial following error can be reduced almost to zero with the help of the feedforward
control. This feedforward control is therefore also called "following error compensation".
Particularly during acceleration in contour curvatures, e.g. circles and corners, this following
error leads to undesirable, velocity-dependent contour violations.
Feedforward control methods
The following feedforward control methods can be used to implement "following error
compensation":
● Speed feedforward control (velocity dependent)
● Torque feedforward control (acceleration dependent)
Activating
The required method of feedforward control must be selected for the relevant axis/spindle
with the following machine data:
MD32620 $MA_FFW_MODE (feedforward control mode)
Value
0
1
2
3
4
Whether the feed forward control is to be selected from the set state of the machine data:
MD32620 $MA_FFW_MODE (method of feedforward control)
or it can be switched additionally from the part program is defined by the axis-specific
machine data:
MD32630 $MA_FFW_ACTIVATION_MODE (activate feedforward control from program)
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
coupled to SINUMERIK 840D / 840D sl / 840 Di / 840Di sl
linked to SIMODRIVE 611 digital (option for SINUMERIK 840D)
Note
The torque type of feedforward control is not supported by the SIMODRIVE 611 universal
drive on the SINUMERIK 840D sl, SINUMERIK 840Di / 840Di sl / 840D with
PROFIBUS-DP.
Description
No feedforward control
Speed feed forward control with PT balancing (standard setting for 840D / 840Di)
Torque feed forward control with PT1 balancing
Speed feed forward control with PT1 balancing (standard setting for 840D sl / 840Di sl)
Torque feed forward control with Tt balancing
5.5 Dynamic feedforward control (following error compensation)
Compensations (K3)
383