Siemens SINUMERIK 840D sl Programming Manual page 103

Further information
Calculation of the spindle speed
The ENS position of the face axis (radius) is the basis for calculating the spindle speed from
the programmed cutting rate.
Note
Frames between WCS and SZS (e.g. programmable frames such as SCALE, TRANS or
ROT) are taken into account in the calculation of the spindle speed and can bring about a
change in speed (for example, if there is a change in the effective diameter in the case of
SCALE).
Speed limitation LIMS
If a workpiece that varies greatly in diameter needs to be machined, it is advisable to specify
a speed limit for the spindle with LIMS (maximum spindle speed). This prevents excessively
high speeds with small diameters. LIMS is only applied when G96, G961, and G97 are active.
LIMS is not applied when G971is selected.
Note
On loading the block into the main run, all programmed values are transferred into the setting
data.
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
6.3 Constant cutting rate (G96/G961/G962, G97/G971/G972, G973, LIMS, SCC)
Spindle motion
103