Position Controller, Position Setpoint Filter: Jerk Filter - Siemens SINUMERIK 840D sl Function Manual

Different servo gain display values (K
● The gear ratios do not match in one or several axes.
● The feedforward control setting data does not match.
Setting the equivalent time constant of the current control loop (MD32800)
The activation of the torque feedforward control filter is performed with:
MD32620 $MA_FFW_MODE = 4
The same rules and recommendations apply to setting the time constant of the current control
loop MD32800 $MA_EQUIV_CURRCTRL_TIME as to the speed feedforward control.
Limitation to stiff machines
Experience has shown that this expenditure is only worthwhile in the case of very stiff
machines, and requires appropriate experience. The elasticities of the machine are often
excited due to the injection of the torque so strongly that the existing vibrations neutralize the
gain in contour accuracy.
In this case, it would be worth trying Dynamic Stiffness Control (DSC) as an alternative:
MD32640 $MA_STIFFNESS_CONTROL_ENABLE = 1
Note
If DSC is to be activated (MD32640 = 1), no parameters may be assigned for actual-value
inversion in the NC (MD32110 $MA_ENC_FEEDBACK_POL = -1).
In DSC mode, actual-value inversion may only be undertaken in the drive (SINAMICS
parameter p0410).
Control response with POWER ON, RESET, REPOS, etc.
In the case of POWER ON and RESET, as well as with "Enable machine data", the setting
data of the feedforward control is read in again (see the appropriate values of the machine
data).
Mode change, block search and REPOS have no influence on the feedforward control.
7.6.2

Position controller, position setpoint filter: Jerk filter

Function
In some applications, such as when milling sculptured surfaces, it can be advantageous to
smooth the position setpoint curves using the jerk filter to obtain better surfaces by reducing
the excitations of machine vibrations. The filter effect of the position setpoints must be as strong
as possible without impermissibly affecting contour accuracy. The smoothing behavior of the
filter must also be as "symmetrical" as possible, i.e. if the same contour was to be traversed
both forward and backward, the characteristic rounded by the filter should be as similar as
possible in both directions.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
G2: Velocities, setpoint / actual value systems, closed-loop control
) usually point to the following:
V
7.6 Optimization of the control
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