Siemens SINUMERIK 840D sl Function Manual page 1169

The absolute offset is calculated with respect to the machine coordinate system and depending
on the orientation of the measuring system (equidirectional or inverse) as:
Orientation of the measuring system
Equidirectional
Opposite direction
Reference point deviation
After determining the absolute offset and the entry in MD34090, the reference point traversing
for the machine axis must be carried out once more.
Referencing methods
Referencing with distance-coded reference marks can be performed in one of two ways:
● Evaluation of two consecutive reference marks:
MD34200 $MA_ENC_REFP_MODE (referencing mode) = 3
Advantage:
– Short travel path
● Evaluation of four consecutive reference marks:
MD34200 $MA_ENC_REFP_MODE = 8
Advantage:
– Plausibility check by NC is possible
– Increase in reliability of referencing result
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
WARNING
15.6 Referencing with distance-coded reference marks
Absolute offset
Measured position + displayed actual position
Measured position - displayed actual position
R1: Referencing
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