Siemens SINUMERIK 840D sl Function Manual page 1735

Minimum spindle speed
In order to ensure smooth rotation at low speeds, the spindle speed is not permitted to fall
below a minimum level.
This speed is defined using setting data:
SD43210 $SA_SPIND_MIN_VELO_G25 (minimum spindle speed)
and can be set for each gear step with the machine data:
MD35140 $MA_GEAR _STEP_MIN_VELO_LIMIT (minimum velocity for gear step change)
.
The minimum spindle speed can be changed in the part program with G25.
NC STOP, single block
NC STOP and single block (even at the block boundary) are only active after completion of
thread chaining. All subsequent G33 blocks and the first subsequent nonG33 block are
traversed like a single block.
Premature abortion without destruction
Thread cutting can be aborted without destruction before the end point is reached. This can
be done by activating a retraction motion.
Thread cutting with ROT frame
With ROT frame and G33, G34, G35, alarm 10607 "Thread with frame not executable" is
activated if the rotation causes a change in the thread length and thus the lead. Rotation
around the thread axis is permissible.
Alarm 10607 "Thread with frame not executable" can be suppressed by setting bit 12 in
machine data:
MD11410 $MN_SUPPRESS_ALARM_MASK
, if the ROTstatement is used intentionally in the application.
All other frames are accepted by the NC without alarm. Attention is drawn to the lead-
changing effect of SCALE.
Basic logic functions: Feeds (V1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.1 Path feedrate F
19