component ilowpass "Low-pass filter with integer inputs and outputs";
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 \\fBilowpass\\fR component between the MPG
encoder \\fBcounts\\fR output and the axis \\fRjog-counts\\fR input,
this can be smoothed.
Choose \\fBscale\\fR conservatively so that during a single session
there will never be more than about 2e9/\\fBscale\\fR pulses seen
on the MPG. Choose \\fBgain\\fR according to the smoothing level
desired. Divide the \\fRaxis.\\fIN\\fR.jog-scale\\fR values by
\\fBscale\\fR.""";
pin in s32 in;
pin out s32 out """\\fBout\\fR tracks \\fBin\\fR*\\fBscale\\fR through a low-pass
filter of \\fBgain\\fR per period.""";
param rw float scale = 1024 """A scale factor applied to the output
value of the low-pass filter.""";
param rw float gain = .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""";
variable double value;
function _ "Update the output based on the input and parameters";
license "GPL";
author "Jeff Epler <jepler@unpythonic.net>";
;;
#include <rtapi_math.h>
FUNCTION(_) {
value += (in - value) * gain;
out = (int)(rtapi_s64)floor((value * scale) + 0.5);
}