Parameter Sets Of The Position Controller - Siemens SINUMERIK 840D Function Manual

Use the following system variables to interrogate the status of the filter circuits:
● $VA_DESVAL_FILTERS_ACTIVE - to determine the currently active filter circuit.
● $VA_DESVAL_FILTERS_DELTA_POS indicates the actual position difference between
the filter circuits in order to determine a suitable switchover point. Suitable switchover points
include motion with Constant velocity (acceleration = 0) - or when an axis is at a standstill,
in which the position difference is small. If a switchover is made while an axis is accelerating,
then an acceleration step (jump) can occur, which under certain circumstances can trigger
the contour monitoring function. The switchover is made immediately when requested.
● You can determine the effective delay time of the first and second filter circuit using the
following variables:
$VA_DESVAL_FILTERS_DELAY_1
$VA_DESVAL_FILTERS_DELAY_2
Example
Two switchover position setpoint filter circuits are parameterized with the following attributes
using MD32402 $MA_AX_JERK_MODE = 25:
● With a value of 5, a position setpoint filter, filter type 5 = FIR lowpass is parameterized in the
first position setpoint filter circuit.
● With a value of 20, a position setpoint filter, filter type 2 = moving average calculation
parameterized in the second position setpoint filter circuit.
● To approximate the total delay times of the two filter circuits to each other, use MD32895
$MA_DESVAL_DELAY_TIME.
●
2.5.4

Parameter sets of the position controller

Six parameter sets per machine axis are available to quickly adapt the position control to the
changed machine properties during operation, e.g. a gear change of the spindle, or to adjust
the dynamic response to another axis, e.g. during tapping.
Machine data
A parameter set comprises the following machine data:
Number
31050
31060
32200
32452
32610
36012
32800
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
G2: Velocities, setpoint / actual value systems, closed-loop control
Identifier $MA_
DRIVE_AX_RATIO_DENOM
DRIVE_AX_RATIO_NUMERA
POSCTRL_GAIN
BACKLASH_FACTOR
VELO_FFW_WEIGHT
STOP_LIMIT_FACTOR
EQUIV_CURRCTRL_TIME
Meaning
Denominator load gearbox
Numerator load gearbox
Servo gain factor (K )
V
Backlash compensation
Feedforward control factor
Exact stop coarse/fine factor and zero speed
Equivalent time constant, current control loop for feed‐
forward control
2.5 Closed-loop control
75