Detailed Description
2.17 Jerk filter (axis-specific)
Acceleration (B2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2-33
With SW 5.1 and higher, it is also possible to control the jerk limitation in the position
controller with a new filter based on a smoothing method that incurs few contour errors:
MD32402 AX_JERK_MODE = 1 ; 2nd-order filter (default)
corresponds to SW 1 to SW 4.4
MD32402 AX_JERK_MODE = 2 ; Sliding mean value generation
(New jerk filter with SW 5.1 and higher).
MD32402 AX_JERK_MODE = 3 ; Bandstop filter with SW 6.3 and higher
Modus 2 requires a bit more computation time, but with the same smoothing effect, it results
in lower contour errors or, with the same accuracy, in a smoother contour with smoother
movements. Mode 2 is recommended. Mode 1 is the default mode in SW 1 to SW 4.4 for
compatibility reasons.
For more information about how the jerk filter available with SW 5.1 and higher works
(balancing filter for improving the position setpoints of the position controller), please refer to:
References:
/FB1/ Description of Functions, Basic Machine; Velocities, Setpoint/Actual-Value Systems,
Regulatory Control (G2), Chapter: "Control Optimization"
Mode 3
There are 2 parameterization options for the bandstop filter:
• "Real bandstop filter":
When identical numerator and denominator natural frequencies are selected (=blocking
frequency). If you select (numerator) damping setting zero, the blocking frequency is
equivalent to complete attenuation.
In this case the 3 dB bandwidth is determined on the following basis:
f
bandwidth
= 2 * f
block.
If instead of complete attenuation, a reduction by a factor of k is all that is required, then
the numerator damping should be selected in accordance with k.
• "Bandstop filter with additional amplitude response increase/decrease at high
frequencies":
In this case, the numerator and denominator natural frequencies are set to different
values. The numerator natural frequency determines the blocking frequency. By selecting
a lower (higher) denominator natural frequency than the numerator natural frequency,
you can increase (decrease) the amplitude response at high frequencies. An amplitude
response increase at high frequencies can be justified in most cases, as the controlled
system generally possesses a lowpass characteristic itself, i.e., the amplitude response
drops at high frequencies anyway.
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