Siemens SINUMERIK 840DE SL - 2.5.4 Phase 1: Reference mark search

Detailed Description
2.5 Referencing with distance-coded reference marks
Reference Point Approach (R1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2-25
2.5.4 Phase 1: Reference mark search
Phase 1: Start
For information on starting reference point approach, refer to "Axis-specific referencing" and
"Channel-specific referencing."
Reference cam
In measuring systems with distance-coded reference marks, reference cams are not
required for the actual referencing action. For functional reasons, however, a reference cam
is required for channel-specific reference point approach and reference point approach from
the part program (G74) before the traversing range end of the machine axis.
Phase 1: Sequence
Sequence without touching a reference cam
Once reference point approach is started, the machine axis accelerates to the assigned
reference point creep velocity:
MD34040 $MA_REFP_VELO_SEARCH_MARKER (reference point creep velocity)
Once the parameterized number of reference marks has been crossed, the machine axis is
stopped again and the actual value system of the machine axis is synchronized to the
absolute position calculated by the NC.
Sequence when starting from the reference cam
If at the start of reference point approach the machine axis is positioned on the reference
cam, the machine axis accelerates to the assigned reference point creep velocity:
MD34040 $MA_REFP_VELO_SEARCH_MARKER (reference point creep velocity)
along the assigned reference point approach direction:
MD34010 $MA_CAM_DIR_IS_MINUS (reference point approach in minus direction)
i.e., away from reference cam. That ensures that the machine axis does not reach the travel
range limit before it has crossed the parameterized number of reference marks.
Once the parameterized number of reference marks has been crossed, the machine axis is
stopped again and the actual value system of the machine axis is synchronized to the
absolute position calculated by the NC.