NAME

       ilowpass - Low-pass filter with integer inputs and outputs

SYNOPSIS

       loadrt ilowpass [count=N|names=name1[,name2...]]

DESCRIPTION

       While  it may find other applications, this component was written to create smoother motion while jogging
       with an MPG.

       In a machine with high acceleration, a short jog can behave almost like a step function.  By putting  the
       ilowpass  component  between  the  MPG  encoder  counts output and the axis jog-counts input, this can be
       smoothed.

       Choose scale conservatively so that during a single session there will never be more than about 2e9/scale
       pulses seen on the MPG.  Choose gain according to the smoothing level desired.   Divide  the  axis.N.jog-
       scale values by scale.

FUNCTIONS

       ilowpass.N (requires a floating-point thread)
              Update the output based on the input and parameters.

PINS

       ilowpass.N.in s32 in
       ilowpass.N.out s32 out
              out tracks in*scale through a low-pass filter of gain per period.

PARAMETERS

       ilowpass.N.scale float rw (default: 1024)
              A scale factor applied to the output value of the low-pass filter.

       ilowpass.N.gain float rw (default: .5)
              Together  with  the  period, sets the rate at which the output changes.  Useful range is between 0
              and 1, with higher values causing the input value to be tracked more  quickly.   For  instance,  a
              setting  of  0.9  causes  the  output  value  to go 90% of the way towards the input value in each
              period.

AUTHOR

       Jeff Epler

LICENSE

       GPL

LinuxCNC Documentation                             2025-06-19                                        ILOWPASS(9)