Closed-Loop Position Control; General Features; Position Actual Value Conditioning; Features - Siemens SINAMICS S120 Function Manual

Function modules

8.7 Closed-loop position control

8.7 Closed-loop position control
8.7.1

General features

The position controller essentially comprises the following parts:
● Position actual value conditioning (including the lower-level measuring probe evaluation
and reference mark search)
● Position controller (including limits, adaptation and the pre-control calculation)
● Monitoring functions (including standstill, positioning, dynamic following error monitoring
and cam signals)
● Position tracking of the load gear (motor encoder), using absolute encoders for rotary
axes (modulo) as for linear axes.
8.7.2

Position actual value conditioning

8.7.2.1

Features

● Correction value (p2512, p2513)
● Setting value (p2514, p2515)
● Position offset (p2516)
● Position actual value (r2521)
● Velocity actual value (r2522)
● Motor revolutions (p2504)
● Load revolutions (p2505)
● Spindle pitch (p2506)
● Position tracking (p2720ff)
8.7.2.2

Description

The actual position value processing converts the actual position value into a neutral
distance unit LU (Length Unit). To do this, the function block uses the encoder evaluation /
motor control with the available encoder interfaces Gn_XIST1, Gn_XIST2, Gn_STW and
Gn_ZSW. These just provide position information in encoder pulses and fine resolution
(increments).
The actual position value is conditioned, regardless of whether the position controller is
enabled immediately after the system has booted, as soon as valid values are received via
the encoder interface.
Parameter p2502 (encoder assignment) is used to define from which encoder (1, 2 or 3), the
actual position value is sensed.
448
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Drive functions