Siemens SINAMICS S150 - Page 356

Functions, monitoring, and protective functions
9.4 Extended functions
Drive converter cabinet units
356 Operating Instructions, 07/07, A5E00288214A
● Fine resolution per revolution (p0419)
● Virtual number of stored revolutions of a rotary absolute encoder (p2721)
● Load gearbox ratio (p2504/p2505)
● Measuring gearbox ratio (p0433/p0432), if p0411.0 = 1
Example: Absolute encoder can count 8 encoder revolutions (p0421 = 8)
Note
Load gearbox problems and solutions, see example in "Position tracking/Measuring
gearbox".
Position range extension example
With absolute encoders without position tracking, it must be ensured that the traversing
range is 0 smaller than half the encoder range, because, beyond this range, no unique
reference remains after switch-on and switch-off (see description on parameter p2507). This
traversing range can be extended using the virtual multiturn (p2721).
The absolute encoder in this example can count 8 encoder revolutions (p0421 = 8).
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Figure 9-17 Load gearbox position tracking (p2721 = 24)
In this example, this means:
● Without position tracking, the position for +/- 4 encoder revolutions about r2521 = 0 LU
can be reproduced.
● With position tracking, the position for +/- 12 encoder revolutions can be reproduced
(p2721 = 24).
For reasons of presentation, the above example is not realistic.
For a rotary axis, a value for p2721 = p0421 is set for an encoder.