Speed Feedforward Control - Siemens SINUMERIK 840D sl Function Manual

Please note the following in this context:
A block search stop is not effective for command or PLC axes traversing asynchronously to
the subprogram processing. To ensure that FFWON/FFWOF only has an effect on the
axis/spindle when it is next stationary in the axis mode, you must explicitly set MD32630 = 2
for each axis/spindle in the axis mode (see also "Forward feed control for command- and
PLC axes (Page 406)").
5.5.2

Speed feedforward control

Function
In the case of speed feedforward control, a velocity setpoint is also applied directly to the
input of the speed controller. With this value the following error can be reduced to nearly
zero (i.e. system deviation is 0) when the velocity is constant.
Commissioning
The following axis-specific parameters must be defined for the speed feedforward control
during commissioning:
Equivalent time constant of the speed control loop (MD32810)
The equivalent time constant of the speed control loop must be determined accurately (e.g.
graphically from a speed setpoint step response) and entered into the following machine
data to correctly set the speed feedforward control:
MD32810 $MA_EQUIV_SPEEDCTRL_TIME (equivalent time constant speed control loop for
feedforward control)
Reference:
Function Manual Basic Functions; Velocities, Setpoint/Actual Value Systems, Closed-Loop
Control (G2), Chapter: "Optimizing the closed-loop control"
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
5.5 Dynamic feedforward control (following error compensation)
K3: Compensation
401