Siemens SINUMERIK 828D Function Manual page 1372

V1: Feedrates
17.2 Path feedrate F
When G97, G971 is active, an S value can be reprogrammed to define a new spindle speed. This will not modify
the cutting rate programmed in G96, G961.
G97, G971 can be used to avoid speed variations in movements along the transverse axis without machining
(e.g. cutting tool).
Note
G96, G961 is only active during workpiece machining (G1, G2, G3, spline interpolation, etc.,
where feedrate F is active).
The response of the spindle speed for active G96, G961 and G0blocks can be defined in the
channel­specific machine data:
MD20750 ALLOW_G0_IN_G96 (G0 logic for G96, G961)
When constant cutting rate G96, G961 is selected, no gear stage change can take place.
The spindle speed override switch acts on the spindle speed calculated.
A DRF offset in the transverse axis does not affect the spindle speed setpoint calculation.
At the start of machining (after G0) and after NC Stop, G60, G09, ... the path start waits for
"nAct= nSet".
The interface signals "nAct = nSet" and "Set speed limited" are not modified by internal
speed settings.
When the speed falls below the minimum speed or if the signal "Axis/spindle stationary" is
recognized, "nAct =nSet" is reset.
A path operation, which has started (G64, rounding), is not interrupted.
Spindle speed limitation with G96, G961
For the function "Constant cutting rate", in setting data:
SD43230 $SA_SPIND_MAX_VELO_LIMS
(spindle speed limitation with G96/G961)
and in the part program (for the master spindle) with the programming command LIMS, a maximum spindle
speed can be set.
The most recently changed value (LIMS or SD) is active.
LIMS is effective with G96, G961, G97 and can be specified on up to four speed limitations in the part program in
one block. Spindle number Sn=1, 2, 3, or 4 of the master spindle that is possible in the particular instance can be
programmed in part progam instruction LM[Sn].
Note
When the block is loaded in the main run, all programmed values are transferred to to setting
data SD43230 $SA_SPIND_MAX_VELO_LIMS.
The speed limit set with LIMS remains stored after the control is switched off, depending on the machine data:
MD10710 PROG_SD_RESET_SAVE_TAB[n] (setting data to be updated).
When G96, G961, G97 are reactivated, this spindle speed limitation is also activated.
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions