Siemens SINUMERIK 840D Function Manual page 301

Case 1: The machine axis is positioned before the reference cam
After the start of reference point approach, the machine axis is accelerated in the
parameterized direction and to the parameterized reference point approach velocity :
● MD34010 $MA_REFP_CAM_DIR_IS_MINUS (reference point approach in minus
direction)
● MD34020 $MA_REFP_VELO_SEARCH_CAM (reference point approach velocity)
The reaching of the reference cam must detected by querying a digital input in the PLC user
program and communicated to the NC via the following interface signal:
DB31, ... DBX12.7 = 1 (reference point approach deceleration)
With detection of the NC/PLC interface signal, the machine axis is decelerated to zero speed.
Whereby at least the distance s
reference cam in Phase 2 with the parameterized reference point creep velocity.
Phase 1 is now complete. Reference point approach is continued with Phase 2.
Figure 10-4 Minimum distance for deceleration
Case 2: The machine axis is positioned on the reference cam
The machine axis remains at its starting position.
Phase 1 is now complete. Reference point approach is continued with Phase 2.
Case 3: The machine axis has no reference cam
Machine axes without reference cams remain at their starting position.
These include, for example:
● Machine axes that only have one zero mark along their entire traversing range
● Rotary axes that only have one zero mark per revolution
Zero must be entered in the following machine data for machine axes without a reference cam:
MD34000 $MA_REFP_CAM_IS_ACTIVE = 0 (axis with reference cam)
Phase 1 is now complete. Reference point approach is continued with Phase 2.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
10.5 Referencing with incremental measurement systems
is traversed. This ensures that the machine axis leaves the
min
R1: Referencing
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