Siemens SINUMERIK 840Di Function Manual page 1451

Phase 2: Sequence
In Phase 2, there are two cases, depending on the assigned synchronization method:
MD34050 $MA_REFP_SEARCH_MARKER_REVERSE (direction reversal on reference
cam):
1. Synchronization with falling reference cam edge:
2. Synchronization with rising reference cam edge:
Case 1: Synchronization with falling reference cam signal edge
During synchronization with falling reference cam edge, 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 (traversing direction of Phase 1):
MD34010 $MA_REFP_CAM_DIR_IS_MINUS (approach reference point in minus direction).
After the reference cam is exited:
DB31, ... DBX12.7 (deceleration of reference point approach) = 0,
the machine axis waits for the next encoder zero mark.
As soon as the encoder zero mark is detected, Phase 2 comes to an end. The machine axis
continues at constant velocity and reference point approach is continued with phase 3.
Reference Point Approach (R1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
MD34050 $MA_REFP_SEARCH_MARKER_REVERSE = 0
MD34050 $MA_REFP_SEARCH_MARKER_REVERSE = 1
Note
If, while approaching the reference cam, the actual velocity of the machine axis does not
reach the set velocity of Phase 2 within the assigned tolerance limits:
MD35150 $MA_SPIND_DES_VELO_TOL (spindle speed tolerance)
Phase 1 is started over again.
This will be the case, for example, if the machine axes are positioned at the reference
cam when reference point approach starts.
2.4 Referencing with incremental measurement systems
Detailed Description
2-11