Siemens SINAMICS S120 Getting Started page 142

Performing basic parameterization
6.3 Drive axes
Figure 6-8
It is important that the multiturn information is still sufficient to record all revolutions which are
important for determining the position at start-up. If all values lie outside the quadrants,
uncontrolled movements of the axis can occur.
☐
Precondition
● You have completely specified and configured the motor used in the device configuration
of the drive axis.
Note
This basic parameterization cannot be performed without having completed this full
configuration.
Extrapolating position values
This parameter is displayed only for pure SSI encoders, namely, for encoders without
HTL/TTL or SIN/COS tracks. Because, compared with the speed controller cycle of the
SINAMICS, the serial transfer is relatively slow, the data can already be obsolete on arrival
at the Sensor Module. If the data transfer is not fast enough, you may need to switch to
encoders with a faster data transmission rate.
1. Activate "Extrapolate position values " in order to extrapolate the SSI data for the next
speed controller cycle.
– Advantage: The dead time between two speed controller cycles reduces and the
– Disadvantage: For fluctuating speeds, the extrapolated value accuracy can vary.
2. Evaluate the advantages and disadvantages carefully.
3. Also check the deployed baud rate. A higher baud rate may allow a sufficiently fast data
transmission.
140
Encoder actual values X_IST1
"Drive axis > Parameters > Basic parameterization > Actual value processing"
closed-loop controller becomes more dynamic.
Getting Started, 12/2018, 6SL3097-5AG30-0BP0