Reference Point Approach (Incremental Measuring System) - Siemens SINAMICS S120 Function Manual

Function modules
9.8 Basic positioner
Procedure
Proceed as follows to carry out the "Absolute encoder adjustment with offset acceptance"
procedure:
1. Enter the offset value, determined when commissioning the drive for the first time, into
parameter p2525.
2. Call "Absolute encoder adjustment with offset acceptance" using parameter p2507 = 4 to
accept the offset value and to link with the adjustment point.
Please observe the following information relevant for this particular step:
– The offset value is used to calculate the position actual value (r2521). Using value "3",
– The offset value is immediately accepted, and is active without the system having to be
3. Save the offset of the absolute encoder adjustment in p2525 in a non-volatile fashion in
(RAM to ROM).
Note
After being commissioned for the first time, carefully ensure that the drive train and its
configuration have not been 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.
4. Check the following machine positions: Check the end positions, software limit switches and
reference point using a test run at a low velocity.
Referencing with DRIVE-CLiQ encoders
DRIVE-CLiQ encoders are available as either "multiturn" or "singleturn" absolute encoders. If
the "referencing" function is selected via the PROFIdrive encoder interface and if a DRIVE-
CLiQ encoder or other type of absolute encoder is connected via the DRIVE-CLiQ interface, the
zero point of the singleturn position is used as the reference point.
Further information on commissioning DRIVE-CLiQ encoders is provided in the SINAMICS
S120 Commissioning Manual.
9.8.4.1

Reference point approach (incremental measuring system)

Function description
With the reference point approach (in the case of an incremental measuring system), the drive
is moved to its reference point. In so doing, the drive itself controls and monitors the complete
referencing cycle.
Incremental measuring systems require that after the machine has been powered up, the
absolute dimension reference is established to the machine zero point. When powering-up the
actual position value x
478
parameter p2507 signals that the adjustment is valid. In addition, bit r2684.11 (=
reference point set) is set to a value of "1".
restarted. If the drive had identified the adjustment, then note (Alarm A7441) is
displayed. The user is prompted to save the adjustment from RAM to ROM.
in the non-referenced state is set to x
0
= 0. Using the reference point
0
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions