Siemens SINUMERIK 840D sl Function Manual page 384

Compensations (K3)
5.5 Dynamic feedforward control (following error compensation)
Value
0
1
2
Upgrading of 840D sl and 840Di sl
While upgrading SINUMERIK 840 D sl and 840Di sl, new commissioning settings must be
entered.
Note
MD32620 $MA_FFW_MODE = 3
If the above-mentioned feedforward control version has already been used earlier, while
upgrading the software, the commissioning setting of
MD32810 $MA_EQUIV_SPEEDCTRL_TIME
(Equivalent time constant speed control loop for feedforward control)
must be reconfigured, because Ti and To are set automatically. these values must be
corrected manually in MD32810.
Activation/deactivation in part program
The feedforward control can also be activated and deactivated by means of the following
high-level language elements in the part program:
FFWON: Feedforward control ON
FFWOF: Feedforward control OFF
The default setting (i.e. M30 even after Reset) is entered in the following channel-specific
machine data:
MD20150 $MC_GCODE_RESET_VALUES
(initial setting of G groups)
FFWON or FFWOF is used to activate and deactivate respectively the feedforward control of all
axes/spindles in the channel for which the following machine data is set:
MD32630 $MA_FFW_ACTIVATION_MODE = 1
and
MD32620 $MA_FFW_MODE = 1, 2, 3 or 4.
MD 32630 should have identical settings for axes that interpolate with each other.
The feedforward control should only be switched on or off while the axis/spindle is stationary
to prevent jerk. Hence the switchover is delayed automatically up to the next standstill
through block search stop.
384
Description
The method of feedforward control is taken from MD32620.
The feedforward control can be controlled within the part program; the FFWON/FFWOF
instruction comes into effect immediately.
The feedforward control can be controlled within the part program; the FFWON/FFWOF
instruction comes into effect only after the axis stops the next time.
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions