Efficient Networks Siemens Sinamics S120 - Manual (Page 243)

Function modules
7.8 Closed-loop position control
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
243
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Figure 7-10 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 (+/- 12 load revolutions with
load gearbox) can be reproduced (p2721 = 24).
Practical example:
For a linear axis, the value for p2721 is set to 262144 for an encoder with p0421 = 4096.
That means, +/- 131072 encoder revolutions or load revolutions can be reproduced in this
way.
For a rotary axis, a value for p2721 = p0421 is set for an encoder.
Configuration of the load gear (p2720).
The following points can be set by configuring this parameter:
● p2720.0: Activation of position tracking
● p2720.1: Setting the axis type (linear axis or rotary axis)
Here, a rotary axis refers to a modulo axis (modulo offset can be activated through
higher-level control or EPOS). With a linear axis, position tracking is mainly used to
extend the position area (see section: Virtual multiturn encoder (p2721)).
● p2720.2: Reset position
Note
If position tracking of the load gearbox is activated after an adjustment p2507=3 has been
made, the adjustment will be reset.
Another adjustment will reset the position (overruns).
Position tracking can be activated in the FW2.5 SP1 only for a single DDS.
If multiple DDS are configured, it will not be possible to active the position tracking
function.