Siemens SINAMICS S150 Operating Instructions Manual page 357

Configuration of the load gearbox (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
Virtual multiturn encoder (p2721)
With a rotary absolute encoder (p0404.1 = 1) with activated position tracking (p2720.0 = 1),
p2721 can be used to enter a virtual multiturn resolution. This enables you to generate a
virtual multiturn encoder value (r2723) from a singleturn encoder. It must be possible to
display the virtual encoder range via r2723.
For rotary axes with modulo offset, the virtual multiturn resolution (p2721) is preset as p0421
and can be changed.
If, as a result of extension of the multiturn information, the displayable area of r2723 (232
bits) is exceeded, the fine resolution (p0419) must be reduced accordingly.
Tolerance window (p2722)
After switching on, the difference between the stored position and the actual position is
ascertained and, depending on the result, the following is triggered:
● Difference within the tolerance window -> the position is reproduced based on the current
● Difference outside the tolerance window -> an appropriate message (F07449) is output.
The tolerance window is preset to quarter of the encoder range and can be changed.
The position can only be reproduced if, in the powered-down state, if the encoder was
moved through less than half of the range that it can represent. For the standard EQN1325
encoder, this is 2048 revolutions or half a revolution for singleturn encoders.
Note
The ratio stamped on the gearbox type plate is often just a rounded-off value (e.g.1:7.34). If,
for a rotary axis, it is not permissible to have any long-term drift, then the actual ratio of the
gearbox teeth must be requested from the gearbox manufacturer.
Drive converter cabinet units
Operating Instructions, 07/07, A5E00288214A
actual encoder value.
CAUTION
Functions, monitoring, and protective functions
9.4 Extended functions
357