Siemens SINUMERIK 840D sl Programming Manual page 272

Motion commands
9.15 Chamfer, rounding (CHF, CHR, RND, RNDM, FRC, FRCM)
FRC=... :
FRCM=... :
Note
Chamfering/Rounding
If the values programmed for chamfering (CHF/CHR) or rounding (RND/RNDM) are too high
for the contour elements involved, chamfering or rounding will automatically be reduced to an
appropriate value.
No chamfering/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
• A number of blocks specified in the machine data 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 chamfering/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.
272
Non-modal feedrate for chamfering/rounding
Feedrate in mm/min (with active G94) or mm/rev (with active
<value>:
G95)
Modal feedrate for chamfering/rounding
Feedrate in mm/min (with active G94) or mm/rev (with active
<value>:
G95)
FRCM=0 deactivates modal feedrate for chamfering/rounding and
activates the feedrate programmed under F.
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Fundamentals