Siemens Sinamics S110 Function Manual page 245

Absolute encoder adjustment
Absolute encoders must be adjusted while commissioning. After the machine has been
powered-down the position information of the encoder is kept.
When p2507 = 2 is entered, using the reference point coordinate in p2599, an offset value
(p2525) is determined. This is used to calculate the position actual value (r2521). Parameter
p2507 signals the adjustment with a "3" - in addition bit r2684.11 (reference point set) is set
to "1".
The offset of the encoder adjustment (p2525) should be saved in a non-volatile fashion
(RAM to ROM) to permanently save it.
Note
If an adjustment is lost on an already adjusted axis, the axis will remain unadjusted even
when the drive unit is switched OFF/ON. The axis needs to be adjusted again in such cases.
During adjustment with the rotary absolute encoder, a range is aligned symmetrically
around the zero point with half the encoder range within which the position is restored after
switch off/on. If position tracking is deactivated (2720.0 = 0), only one encoder overflow is
permitted in this range (further details are given in the chapter titled Position controller →
Position actual value conditioning). Once adjustment has been carried out, the range must
not be exited because a unique reference between the actual encoder value and the
mechanical components cannot be established outside the range.
If the reference point p2599 is in the encoder range, the actual position value is set in line
with the reference point during adjustment. Otherwise, it is set to a corrected value in the
encoder range.
No overflow occurs with linear absolute encoders, which means that the position can be
restored within the entire traversing range after switch on/off once adjustment has been
carried out. During adjustment, the actual position value is set in line with the reference
point.
Function Manual
Function Manual, 01/2011, 6SL3097-4AB10-0BP3
CAUTION
Drive functions
7.3 Function modules
243