Siemens SINUMERIK 840Di Function Manual page 424

Detailed Description
2.4 Closed-loop control
The speed and current control systems for SIMODRIVE 611 are described in:
References:
/IAD/ "Installation & Startup Guide" SINUMERIK 840D/611D digital
/IAC/ "Installation & Startup Guide" SINUMERIK 810D
/PJU/ "Planning Guide" Converters
The basic structure of an axis/spindle position control is illustrated below:
Fig. 2-12
For a description of the feedforward control, backlash, friction compensation with further
machine data, and leadscrew error compensation, see:
References:
/FB2/Description of Functions, Extended Functions; Compensations (K3).
For a description of jerk limitation, see:
References:
/FB1/Description of Functions, Basic Machine; Acceleration (B2).
Fine Interpolation
The fine interpolator (FIPO) is used to adjust the setpoint of the (generally lower) interpolator
cycle clock to the later position-control cycle.
Fine interpolation further improves the quality of the contour (decreasing the step effect of
the speed setpoint).
There are three types of FIPOs:
1:
2:
3:
2-50
Additional servo parameter sets for position control
Differential FIPO
Cubic FIPO
Cubic FIPO, optimized for operation with feedforward control
Velocities, Setpoint/Actual-Value Systems, Closed-Loop Control (G2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0