Siemens Sinamics V90 Operating Instructions Manual page 256

Control functions
7.5 Internal position control (IPos)
Position area extension
After the position tracking function is activated, the position area can be extended.
Example
An absolute encoder that can represent eight encoder revolutions is used here.
● If the position tracking function is deactivated (p29243 = 0), the position for +/- 4 encoder
revolutions can be reproduced.
● If you activate the position tracking function (p29243 = 1), and set the virtual multi-turn
p29244 = 24, and the gear ratio p29248/p29249 = 1, the position for +/- 12 encoder
revolutions (+/- 12 load revolutions with load gear) can be reproduced.
Mechanical gear configuration
If you are using a mechanical gear between the motor and the load, and using an absolute
encoder to process the position control, an offset occurs (depending on the gear ratio)
between the zero position of the encoder and the load whenever encoder overflow occurs.
Note
If the ratio between the multi-turn resolution and the modulo range (p29246) is not an integer
number, fault F7442 is output.
To make the ratio between the multi-turn resolution and the modulo range an integer number,
observe the following formulas. The ratio v is calculated as follows:
● Motor encoder without position tracking (p29243 = 0):
– For multi-turn encoders:
– For single-turn encoders:
● Motor encoder with position tracking (p29243 = 1):
v = (p29244 × 29247)/p29246
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v = (4096 × p29247 × p29248)/(p29249 × p29246)
v = (p29247 × p29248)/(p29249 × p29246)
SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2019, A5E36037884-007