Siemens SINUMERIK 840D sl Function Manual page 1767

Empty blocks
When chamfer or rounding is active, the possible number of blocks containing no traversing
information is limited.
The maximum number is defined in machine data:
MD20200 CHFRND_MAXNUM_DUMMY_BLOCKS.
The possible blocks without traversing information in the compensation plane are pure
dummy commands and are called empty blocks. For this reason, they may only be written
between two blocks with traversing information.
Constraints
• Feedrate interpolation FLIN and FCUB is not possible for chamfer/rounding.
• FRC/FRCM has no effect if a chamfer is being machined with G0; the command can be
• FRC is only effective if a chamfer/rounding is programmed in the same block or if RNDM
• FRC overwrites the F or FRCM value for chamfer/rounding in the current block.
• FRC/FRCM must be set to a value greater than zero.
• FRCM=0 activates the feedrate programmed in F for the chamfer/rounding.
• If FRCM is programmed, the FRCM value must be reprogrammed, equivalent to F, on a
Basic logic functions: Feeds (V1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
programmed according to the F value without error message.
has been activated.
G94 ↔ G95 change, etc. If only F is reprogrammed and FRCM > 0 before the feedrate type
is changed, error message 10860 (no feedrate programmed) appears.
Detailed description
2.3 Feedrate control
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