Siemens SINUMERIK 840D sl Function Manual page 1633

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.
Spindle speed < Position-control activation speed (Phase 5, 5a)
The spindle is stationary and has reached the end point. Position control is active and holds
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 machine data:
MD36010 $MA_STOP_LIMIT_FINE
and
MD36000 $MA_STOP_LIMIT_COARSE.
Note
The positioning procedure is considered complete when the end-of-positioning criterion is
reached and signaled.
The condition is "Exact stop fine". This applies to SPOS, M19 or SPOSA from the part
program, synchronized actions and spindle positioning by the PLC using FC 18.
Basic logic functions: Spindles (S1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed Description
2.1 Spindle modes
23