Siemens SINUMERIK 840D sl Function Manual page 400

K3: Compensation
5.5 Dynamic feedforward control (following error compensation)
Note
Upgrading 840D sl and 840Di sl
When upgrading SINUMERIK 840 D sl and 840Di sl, new commissioning settings must be
entered.
If the feedforward control version MD32620 = 3 was already used, then when upgrading the
software, the commissioning setting of MD32810 $MA_EQUIV_SPEEDCTRL_TIME
(equivalent time constant, speed control loop for feedforward control) must be re-performed,
as the Ti and To values are automatically taken into account. These values must be
corrected manually in MD32810.
Activation/deactivation in part program
The following axis-specific machine data can be used to define that the feedforward control
for this axis/spindle can be activated and deactivated by the part program:
MD32630 $MA_FFW_ACTIVATION_MODE (activate feedforward control from program)
Value
0
1
2
The feedforward control is activated/deactivated from the part program using the operations:
FFWON: Feedforward control ON
FFWOF: Feedforward control OFF
The default setting (i.e. M30 even after reset) is entered using the channel-specific machine
data:
MD20150 $MC_GCODE_RESET_VALUES (initial setting of G groups)
FFWON/FFWOF is active for all axes/spindles in the axis mode, where:
MD32630 $MA_FFW_ACTIVATION_MODE = 1 (or 2)
and
MD32620 $MA_FFW_MODE = 1, 2, 3 or 4
The identical MD32630 setting should be used for axes that interpolate with each other.
The feedforward control should only be activated or deactivated while the axis/spindle is
stationary in the axis mode, in order to prevent jerky motion. Hence the switchover is
delayed automatically up to the next standstill through block search stop.
400
Significance
The feedforward control cannot be activated and deactivated from the part program. This
means that the state specified using MD32620 $MA_FFW_MODE is always effective for the
axis/spindle.
The feedforward control can be activated and deactivated from the part program. The
operation becomes active immediately.
The feedforward control can be activated and deactivated from the part program. The
operation only becomes active the next time that the axis comes to a standstill.
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions