Siemens SINUMERIK 840D sl Function Manual page 320

Manual and Handwheel Travel (H1)
DRF offset
Applications
The DRF offset can be used, for example, in the following application cases:
● Offsetting tool wear within an NC block
● Highly precise offset during grinding
● Simple temperature compensation
Velocity reduction
The velocity generated by the handwheel for DRF can be reduced as compared to the JOG
velocity via axial machine data
MD32090 $MA_HANDWH_VELO_OVERLAY_FACTOR
(ratio of JOG velocity to handwheel velocity).
DRF active
DRF must be active to allow the DRF offset to be modified by means of traversal with the
handwheel. The following preconditions must be fulfilled:
● AUTOMATIC mode
● DB21, ... DBX0.3 (activate DRF) = 1
The DRF offset can be activated/deactivated for specific channels using the "program
control" function on the HMI user interface.
The HMI software then sets the interface signal:
DB21, ... DBX24.3 (DRF selected) =1
The PLC program (basic PLC program or user program) transfers this interface signal to
interface signal
DB21, ... DBX0.3 (activate DRF) once the corresponding logic operation has been
performed.
320
Where NC blocks have very long processing times, it becomes necessary to offset tool
wear manually within the NC block (e.g. large surface-milling machines).
CAUTION
The work offset introduced via the DRF offset is always effective in all modes and after a
RESET. It can, however, be suppressed non-modally in the part program.
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions