Siemens SINUMERIK 802D sl Programming Manual page 35

04.07
Reference point return operation
Reference point return operation is the series of operations in which the axes re-
turn to the reference point after the reference point return operation has been star-
ted manually.
Reference point return is executed in the following manner:
S After the positioning at the intermediate positioning point B, the axes return di-
rectly to the reference point at a rapid traverse rate. The axes can be returned
to the reference point in a shorter time compared to the normal reference point
return operation that uses a deceleration limit switch for the individual axes.
S Even if point B is located outside the area in which reference point return is allo-
wed, the high-speed reference point return specification allows the axes to re-
turn to the reference point.
S High-speed automatic reference point return is valid only when reference point
return is called by G28, and it does not influence manual reference point return
operation.
Automatic reference point return for rotary axes
With a rotary axis, it is possible to execute the automatic reference point return the
same as with a linear axis. With a rotary axis, if it has been moved by more than
360.000_ from the reference point established first, reference point return is ex-
ecuted to the closest reference point in the preset direction of reference point re-
turn. The illustration below shows how the reference point return is executed from
points A and B. (The reference point return direction is determined by the setting of
MD_$MA_REFP_CAM_IS_MINUS.
--720_
(Reference point return: Plus direction is selected for the reference point return direction)
Fig. 2-10
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SINUMERIK 802D sl/840D/840D sl/840Di/840Di sl/810D ISO Milling (PGM) -- 04.07 Edition
B B'
---360_
Commands Calling Axis Movements
2.2 Reference point return
0
360_
A A'
+
720_
2-35