Siemens SINUMERIK 840D sl Programming Manual page 246

Fundamentals
2.9 Motion commands
RNDM=... :
FRC=... :
FRCM=... :
Note
Chamfer/rounding too high
If the values programmed for chamfer (CHF/CHR) or rounding (RND/RNDM) are too high for
the contour elements involved, chamfer or rounding will automatically be adapted:
1. If MD11411 $MN_ENABLE_ALARM_MASK bit 4 is set, alarm 10833 "Chamfer or rounding
must be reduces" is output (cancel alarm).
2. The chamfer/rounding is reduced until it fits in the contour corner. This results in at least one
block without motion. At this block, the required motion is stopped.
Note
Chamfer/rounding not possible
No chamfer/rounding is performed if:
● No straight or circular contour is available in the plane
● A movement takes place outside the plane
● The plane is changed
● The number of blocks specified in the machine data that are not to contain any information
about traversing (e.g. only command outputs) is exceeded
Note
FRC/FRCM
FRC/FRCM has no effect if a chamfer is traversed with G0; the command can be programmed
according to the F value without error message.
FRC is only effective if a chamfer/rounding is programmed in the block or if RNDM has been
activated.
FRC overwrites the F or FRCM value in the current block.
The feedrate programmed under FRC must be greater than zero.
FRCM=0 activates the feedrate programmed under F for chamfer/rounding.
If FRCM is programmed, the FRCM value will need to be reprogrammed like F on change
G94 ↔ G95, etc. If only F is reprogrammed and if the feedrate type FRCM > 0 before the
change, an error message will be output.
246
Modal rounding (rounding multiple contour corners in the same way one after the other)
Radius of the roundings (unit corresponding to G70/G71)
<value>:
Modal rounding is deactivated with RNDM=0.
Non-modal feedrate for chamfer/rounding
Feedrate in mm/min (with active G94) or mm/rev (with active G95)
<value>:
Modal feedrate for chamfer/rounding
Feedrate in mm/min (with active G94) or mm/rev (with active G95)
<value>:
FRCM=0 deactivates modal feedrate for chamfer/rounding and activates
the feedrate programmed under F.
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming