Siemens SINUMERIK 840D sl Function Manual page 1631

Note
The speed from machine data:
MD36302 $MA_ENC_FREQ_LOW
must be greater than the position-control activation speed
(MD35300 $MA_SPIND_POSCTRL_VELO).
Phase 1
Possible positioning from Phase 1a:
The spindle is rotating at a higher speed than the encoder limit frequency. The spindle is not
synchronized.
Possible positioning from Phase 1b:
The spindle is rotating at a lower speed than the encoder limit frequency. The spindle is
synchronized.
Note
If position control is active, the speed can only amount to 90% of the maximum speed of the
spindle or the encoder limit frequency (10% control reserve required).
Possible positioning from Phase 1c:
The spindle rotates at the programmed spindle speed,
whereby the speed is less than that given in the machine data:
MD35300 $MA_SPIND_POSCTRL_VELO (Position control activation speed)
The spindle is synchronized.
Phase 2
Spindle speed > Position-control activation speed
With the activation of the command SPOS, M19 or SPOSA the deceleration of the spindle
begins with the acceleration given in the machine data:
MD35200 $MA_GEAR_STEP_SPEEDCTL_ACCEL
up to the position control activation speed.
The spindle is synchronized once the encoder limit frequency is undercrossed.
Spindle speed < Position-control activation speed
With the programming of SPOS, M19 or SPOSA the spindle is switched to the position control
mode (if it is not already in the position control mode).
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL (Acceleration in the position control
mode)
will be active. The travel path to the end point is calculated.
The traversing of the spindle up to the programmed target point is carried out optimally in
time.
I.e., the target point is driven at the highest possible speed (maximum MD35300
$MA_SPIND_POSCTRL_VELO).
Depending on corresponding limiting conditions Phases 2 - 3 - 4 - 5,
or 2 - 4a - 5a respectively are executed.
Basic logic functions: Spindles (S1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed Description
2.1 Spindle modes
21