Siemens SINAMICS S120 Function Manual page 488

Function modules
9.8 Basic positioner
Figure 9-19
By using a reduction gear between the motor and the load or spindle, the drive detects several
revolutions of the motor per mechanical revolution of the load - and therefore also several
encoder zero marks.
Since the higher-level control or position control when referencing requires a unique reference
between the encoder zero mark and the machine axis (load/spindle), the "correct" zero mark is
selected using a BERO signal.
Referencing with a measuring gearbox
The following figure shows an application example for using referencing with several zero
marks per revolution with a measuring gear located between the motor/load and encoder.
Figure 9-20
As a result of the measuring gear, several encoder zero marks appear within one motor/load
revolution. Using the BERO signal, also here, the correct zero mark for referencing can be
selected from the several encoder zero marks.
486
Gearbox between motor and spindle
Measuring gear between the motor and encoder
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions