kmobs/frequencytester.md

## frequencytester.md

      
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              frequencytester.md
            
          
    Frequency Testing

This will allow you to test a specific frequency that you hear when you do your resonance testing in Klipper and potentially track down where extra peaks are coming from. If something is rattling at a specific frequency, you can specify that frequency and feel around the printer until you track it down.
Code was adopted by zifnab from somewhere in Klipper.
Usage

You have to have [resonance_holder] in your printer.cfg.
The command is HOLD_RESONANCE AXIS=<axis> FREQ=int SECONDS=<seconds>
Place the following in klippy/extras/resonance_holder.py and restart klipper (not firmware restart) to gain the module.
import logging, math, os, time

class TestAxis:
    def __init__(self, axis=None, vib_dir=None):
        if axis is None:
            self._name = "axis=%.3f,%.3f" % (vib_dir[0], vib_dir[1])
        else:
            self._name = axis
        if vib_dir is None:
            self._vib_dir = (1., 0.) if axis == 'x' else (0., 1.)
        else:
            s = math.sqrt(sum([d*d for d in vib_dir]))
            self._vib_dir = [d / s for d in vib_dir]
    def matches(self, chip_axis):
        if self._vib_dir[0] and 'x' in chip_axis:
            return True
        if self._vib_dir[1] and 'y' in chip_axis:
            return True
        return False
    def get_name(self):
        return self._name
    def get_point(self, l):
        return (self._vib_dir[0] * l, self._vib_dir[1] * l)

def _parse_axis(gcmd, raw_axis):
    if raw_axis is None:
        return None
    raw_axis = raw_axis.lower()
    if raw_axis in ['x', 'y']:
        return TestAxis(axis=raw_axis)
    dirs = raw_axis.split(',')
    if len(dirs) != 2:
        raise gcmd.error("Invalid format of axis '%s'" % (raw_axis,))
    try:
        dir_x = float(dirs[0].strip())
        dir_y = float(dirs[1].strip())
    except:
        raise gcmd.error(
                "Unable to parse axis direction '%s'" % (raw_axis,))
    return TestAxis(vib_dir=(dir_x, dir_y))


class ResonanceHolder:
    def __init__(self, config):
        self.printer = config.get_printer()
        self.gcode = self.printer.lookup_object('gcode')
        self.accel_per_hz = config.getfloat('accel_per_hz', 75., above=0.)
        self.gcode.register_command("HOLD_RESONANCE", self.cmd_HOLD_RESONANCE, desc=self.cmd_HOLD_RESONANCE_help)

    def hold(self, gcmd, axis, seconds, freq):
        '''holds a resonance for N seconds
           resonance code taken from klipper's test_resonances command'''
        end = time.time() + seconds
        toolhead = self.printer.lookup_object('toolhead')
        X, Y, Z, E = toolhead.get_position()
        sign = 1.
        input_shaper = self.printer.lookup_object('input_shaper', None)
        if input_shaper is not None and not gcmd.get_int('INPUT_SHAPING', 0):
            input_shaper.disable_shaping()
            gcmd.respond_info("Disabled [input_shaper] for resonance holding")
        else:
            input_shaper = None
        gcmd.respond_info("starting freq %i for %i seconds" % (freq, seconds))
        while time.time() < end:
            t_seg = .25 / freq
            accel = self.accel_per_hz * freq
            max_v = accel * t_seg
            toolhead.cmd_M204(self.gcode.create_gcode_command(
                "M204", "M204", {"S": accel}))
            L = .5 * accel * t_seg**2
            dX, dY = axis.get_point(L)
            nX = X + sign * dX
            nY = Y + sign * dY
            toolhead.move([nX, nY, Z, E], max_v)
            toolhead.move([X, Y, Z, E], max_v)
            sign = -sign
        gcmd.respond_info("DONE")


    cmd_HOLD_RESONANCE_help = ("Holds resonance for n seconds")
    def cmd_HOLD_RESONANCE(self, gcmd):
        axis = _parse_axis(gcmd, gcmd.get("AXIS").lower())
        freq = gcmd.get("FREQ", parser=int)
        seconds = gcmd.get("SECONDS", parser=int)
        self.hold(gcmd, axis, seconds, freq)

def load_config(config):
    return ResonanceHolder(config)