Siemens SINUMERIK 840Di Function Manual page 1520

Detailed Description
2.1 Spindle modes
Phase 4
Spindle speed > Position-control activation speed
The spindle brakes from the calculated "braking point" with machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL
to the end point.
Spindle speed < Position-control activation speed
At the time identified by the braking start point calculation in phase 3,
the spindle brakes to standstill with the acceleration from machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL.
Phase 4a:
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 standstill with the acceleration in machine data:
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL.
Phase 5
Spindle speed > Position-control activation speed
Position control remains active and holds the spindle in the programmed position.
Note
The maximum encoder limit frequency of the spindle position actual-value encoder is
monitored by the control (it may be exceeded); in position control mode, the setpoint speed
is reduced to 90% of the measurement system limit speed.
NC/PLC IS:
DB31, ... DBX83.1 (programmed speed too high)
is set.
If "MS limit frequency exceeded"
is still pending following a reduction in the setpoint speed, an alarm is output.
2-16
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Spindles (S1)