Siemens SINUMERIK 840D sl Function Manual page 1219

until the braking start point calculation identifies the point at which the programmed spindle
position can be approached accurately with the defined acceleration.
Case 2: Spindle synchronized
To reach the end point, the spindle is accelerated up to the speed defined in machine data:
MD35300 $MA_SPIND_POSCTRL_VELO.
This is not exceeded.
The braking start point calculation identifies when the programmed spindle position can be
approached accurately at the acceleration defined in machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL.
At the point, which is determined by the braking start point calculation in Phase 1, the spindle
decelerates to a standstill with the acceleration given in the following machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL
Phase 3
At the point, which is determined by the braking start point calculation in Phase 2, the spindle
decelerates to a standstill with the acceleration given in the following machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL
Phase 3a:
When the SPOS command is activated the proximity of the end point is such that the spindle
can no longer be accelerated up to machine data:
MD35300 $MA_SPIND_POSCTRL_VELO.
The spindle is braked to a standstill with the acceleration given in the following machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL
Phase 4, 4a
The spindle is stationary and it has reached the position. The position control is active and
stops the spindle in the programmed position.
NC/PLC IS:
DB31, ... DBX60.6 (Position reached with exact stop coarse)
and
DB31, ... DBX60.7 (Position reached with exact stop fine)
are set if the distance between the spindle actual position and the programmed position
(spindle setpoint position) is less than the settings for the exact stop fine and coarse limits.
This is defined in the machine data:
MD36010 $MA_STOP_LIMIT_FINE
MD36000 $MA_STOP_LIMIT_COARSE
Phase 3:
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
S1: Spindles
16.2 Modes
1219