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Tolerance window (p0413)
After switching on, the difference between the stored position and the actual position is
determined and, depending on the result, the following is initiated:
● Difference within the tolerance window
The position is reproduced based on the actual encoder value.
● Difference outside the tolerance window:
fault F07449 is output.
● The tolerance window is preset to quarter of the encoder range and can be changed.
Note
Reproduce the position
The position can only be reproduced if, in the powered-down state, 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 single-turn encoders.
Note
Actual transformation ratio is required
The ratio stamped on the gear rating 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 gear
teeth must be requested from the gear manufacturer.
Synchronous motors with measuring gear
Field-oriented control of synchronous motors requires a clear reference between the pole
position and encoder position. This reference must also be carefully maintained when using
measuring gears: This is the reason that the ratio between the pole pair number and the
encoder revolutions must be an integer multiple and ≥ 1 (e.g. pole pair number 17,
measuring gear 4.25, ratio = 4).
Commissioning
The position tracking of the measuring gear can be activated in the drive wizard (STARTER)
during the configuration of the drive. During the configuration there is an item for encoder
parameterization. In the encoder dialog, click on the "Details" button and activate the
checkbox for position tracking in the displayed dialog.
The parameters p0412 (Measuring gear, rotary absolute encoder, revolutions, virtual) and
p0413 (Measuring gear, position tracking tolerance window) can only be set via the expert
list.
Precondition
● Absolute encoder
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
Functions, monitoring and protective functions
9.3 Drive functions
607
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