Siemens SINUMERIK 840D Function Manual page 804

S1: Spindles
18.4 Configurable gear adaptations
MD35300 $MA_SPIND_POSCTRL_VELO
The NC/PLC interface signals "Spindle override"/"Feedrate override" at
DB31, ... DBX17.0=0: DB31, ... DBB19)
as well as:
DB31, ... DBX17.0=1: DB31, ... DBB0
are effective as normal for positioning.
The positioning speed can be changed proportionally through the program statement
OVRA[Sn].
Note
OVRA[Sn] is valid modally. After the gear stage change, a value appropriate for the machining
should be reset.
The part program statement FA[Sn] does not change the positioning speed during gear stage
change.
Acceleration
The acceleration values are determined by the machine data which is configured depending on
the gear stage:
MD35200 $MA_GEAR_STEP_SPEEDCTRL_ACCEL
and
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL
The acceleration can be changed proportionally by programming ACC[Sn].
Note
ACC[Sn] is valid modally. After the gear stage change, a value appropriate for the machining
should be reset.
Speed-dependent acceleration
The "knee-shaped acceleration characteristic" is effective as in positioning with SPOS or FC18.
Jerk
It is currently not possible to limit the change in acceleration.
End of positioning
The transition between the end of the positioning action (DB31, ... DBX84.5)
and the start of oscillation mode (DB31, ... DBX84.6) is defined on
reaching "Exact stop fine" (DB31, ... DB60.7) and the time value entered in machine data:
MD3510 $MA_SPIND_POSIT_DELAY_TIME
.
804
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA