Siemens SINUMERIK 840D Function Manual page 133

G97, G971 can be used to avoid speed variations in motions 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 G0 blocks can be defined in the
channel-specific 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 override switch acts on the calculated spindle speed.
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
A maximum spindle speed can be specified for the "Constant cutting rate" function:
● In the setting data:
SD43230 $SA_SPIND_MAX_VELO_LIMS (spindle speed limitation for G96/G961)
● In the part program (for the master spindle) with the programming command LIMS
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 program command LM[<Sn>].
When the block is loaded in the main run, all programmed values are transferred to the setting
data SD43230 $SA_SPIND_MAX_VELO_LIMS.
Depending on the machine data:
MD10710 PROG_SD_RESET_SAVE_TAB[n] (setting data to be updated),
the speed limit set with LIMS remains stored after the control is switched off.
When G96, G961, G97 are reactivated, this speed limitation is also activated.
The maximum permissible spindle speed defined via G26 or via the setting data:
SD43220 $SA_SPIND_MAX_VELO_G26 (maximum spindle speed)
cannot be exceeded.
In the event of incorrect programming that would cause one of the speed limits (G26 or
SD43220 $SA_SPIND_MAX_VELO_G26) to be exceeded, the following interface signal is set.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
V1: Feedrates
5.2 Path feedrate F
133