Siemens SINAMICS S120 Function Manual page 478

Function modules
9.8 Basic positioner
Absolute encoder adjustment
When commissioning an absolute encoder for the first time, a mechanical axis position is
aligned with the encoder absolute position and then the system is synchronized.
After the drive has been switched off the encoder position information is retained. This means
that the axis does not have to be readjusted when the drive powers up.
Note
It is crucial that absolute encoders are adjusted the first time that they are commissioned.
Requirements
The following requirement must be satisfied before the adjustment:
● The axis is located at a defined reference position.
Procedure
1. Call the adjustment using parameter p2507 = 2.
Please observe the following information relevant for this particular step:
– Using the reference point coordinate in p2599, an offset value is determined and entered
– If the drive had identified the adjustment, then note (Alarm A7441) is displayed. The user
– Note down the offset value that has possibly been determined so that you can enter this
2. Save the offset of the absolute encoder adjustment in p2525 in a non-volatile fashion in
(RAM to ROM).
Please observe the following information relevant for this particular step:
– If an adjustment is lost for an already adjusted axis, the axis will remain unadjusted even
Note
After being commissioned for the first time, carefully ensure that the drive train and its
configuration cannot be mechanically changed or modified. When mechanical changes are
made, the synchronization between the encoder actual value and the machine zero is lost.
In this particular case, it is crucial that the axis is readjusted.
Rotary absolute encoder
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 (p2720.0 = 0), only one encoder overflow is permitted to occur
in this range (for further information, see Chapter Actual position value processing (Page 445)).
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into p2525. The offset value is used to calculate the position actual value (r2521). Using
value "3", parameter p2507 signals that the adjustment is valid. In addition, bit r2684.11
(reference point set) is set to a value of "1".
is prompted to save the adjustment from RAM to ROM.
into p2525 when using the "Absolute encoder adjustment with offset acceptance"
function.
after a POWER ON of the drive. In this particular case, it is crucial that the axis is
readjusted.
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions