Siemens SINUMERIK 840D sl Function Manual page 393

In addition to the response at constant traversal, it is particularly important to monitor the
following error which occurs which the axis/spindle is accelerating. The adjustment criterion
for the torque feedforward control is:
following error ≈ 0
● Case 1:
● Case 2:
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
When the axis is traveling in a positive direction, the recorded following error has a
positive value.
→ the values entered for the equivalent time constant of the current control loop or for the
moment of inertia of the axis are too low.
When the axis is traveling in a positive direction, the recorded following error has a
negative value.
→ the values entered for the equivalent time constant of the current control loop or for the
moment of inertia of the axis are too high.
5.5 Dynamic feedforward control (following error compensation)
Compensations (K3)
393