Measuring Gear - Siemens SINAMICS S120 Function Manual

Basic functions
6.17 Position tracking
6.17.2

Measuring gear

Features
● Configuration via p0411
● Virtual multiturn via p0412
● Tolerance window for monitoring the position at power ON p0413
● Input of the measuring gear via p0432 and p0433
● Display via r0483
Description
If a mechanical gear (measuring gear) is located between an endlessly rotating motor/load
and the encoder and position control is to be carried out using this absolute encoder, an
offset occurs (depending on the gear ratio) between the zero position of the encoder and the
motor/load whenever encoder overflow occurs.
Figure 6-13
In order to determine the position at the motor/load, in addition to the position actual value of
the absolute encoder, it is also necessary to have the number of overflows of the absolute
encoder.
If the power supply of the control module must be powered-down, then the number of
overflows must be saved in a non-volatile memory so that after powering-up the position of
the load can be uniquely and clearly determined.
Example: Gear ratio 1:3 (motor revolutions p0433 to encoder revolutions p0432), absolute
encoder can count 8 encoder revolutions (p0421 = 8).
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Measuring gear
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
Drive functions