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FW version: Stable

param LPF - Low Pass Filter

The lpf is suitable for setting a response of the throttle, the lower the parameter value is the slower the response is. It also can filter wrong sensor readings. An example of the effect of different values of the parameter is shown below.

This type of convention is used not only in listed block (CSC, ASC, PWM), but also in different situations in siliXcon controller. For example in the LYNX application is used this filter for smooth engaging or disengaging of the static brake. The name of this parameter is not lpf but rgnslpup - rgnsldown, but the function is the same as lpf.

Influence of the LPF value to the output​

lpf

lpf parameter value

The parameter represents an inverted time constant (frequency response) of the output filter. For a typical sampling frequency of 1000 Hz, the example values are:

  • 1: filtering is disabled
  • 0.1: 16 Hz cutoff
  • 0.01: 1.6 Hz cutoff
  • 0.001: 0.16 Hz cutoff |

Negative LPF​

In some cases, the lpf parameter accepts a negative value. In this situation, the behavior is changed and the block transfer function is a ramp. This can be done for example in CSC.