mirror of https://github.com/Desuuuu/klipper.git
365 lines
15 KiB
Python
365 lines
15 KiB
Python
# Printer heater support
|
|
#
|
|
# Copyright (C) 2016,2017 Kevin O'Connor <kevin@koconnor.net>
|
|
#
|
|
# This file may be distributed under the terms of the GNU GPLv3 license.
|
|
import math, logging, threading
|
|
import pins
|
|
|
|
|
|
######################################################################
|
|
# Sensors
|
|
######################################################################
|
|
|
|
KELVIN_TO_CELCIUS = -273.15
|
|
|
|
# Thermistor calibrated with three temp measurements
|
|
class Thermistor:
|
|
def __init__(self, config, params):
|
|
self.pullup = config.getfloat('pullup_resistor', 4700., above=0.)
|
|
# Calculate Steinhart-Hart coefficents from temp measurements
|
|
inv_t1 = 1. / (params['t1'] - KELVIN_TO_CELCIUS)
|
|
inv_t2 = 1. / (params['t2'] - KELVIN_TO_CELCIUS)
|
|
inv_t3 = 1. / (params['t3'] - KELVIN_TO_CELCIUS)
|
|
ln_r1 = math.log(params['r1'])
|
|
ln_r2 = math.log(params['r2'])
|
|
ln_r3 = math.log(params['r3'])
|
|
ln3_r1, ln3_r2, ln3_r3 = ln_r1**3, ln_r2**3, ln_r3**3
|
|
|
|
inv_t12, inv_t13 = inv_t1 - inv_t2, inv_t1 - inv_t3
|
|
ln_r12, ln_r13 = ln_r1 - ln_r2, ln_r1 - ln_r3
|
|
ln3_r12, ln3_r13 = ln3_r1 - ln3_r2, ln3_r1 - ln3_r3
|
|
|
|
self.c3 = ((inv_t12 - inv_t13 * ln_r12 / ln_r13)
|
|
/ (ln3_r12 - ln3_r13 * ln_r12 / ln_r13))
|
|
self.c2 = (inv_t12 - self.c3 * ln3_r12) / ln_r12
|
|
self.c1 = inv_t1 - self.c2 * ln_r1 - self.c3 * ln3_r1
|
|
def calc_temp(self, adc):
|
|
r = self.pullup * adc / (1.0 - adc)
|
|
ln_r = math.log(r)
|
|
inv_t = self.c1 + self.c2 * ln_r + self.c3 * ln_r**3
|
|
return 1.0/inv_t + KELVIN_TO_CELCIUS
|
|
def calc_adc(self, temp):
|
|
inv_t = 1. / (temp - KELVIN_TO_CELCIUS)
|
|
if self.c3:
|
|
y = (self.c1 - inv_t) / (2. * self.c3)
|
|
x = math.sqrt((self.c2 / (3. * self.c3))**3 + y**2)
|
|
ln_r = math.pow(x - y, 1./3.) - math.pow(x + y, 1./3.)
|
|
else:
|
|
ln_r = (inv_t - self.c1) / self.c2
|
|
r = math.exp(ln_r)
|
|
return r / (self.pullup + r)
|
|
|
|
# Thermistor calibrated from one temp measurement and its beta
|
|
class ThermistorBeta(Thermistor):
|
|
def __init__(self, config, params):
|
|
self.pullup = config.getfloat('pullup_resistor', 4700., above=0.)
|
|
# Calculate Steinhart-Hart coefficents from beta
|
|
inv_t1 = 1. / (params['t1'] - KELVIN_TO_CELCIUS)
|
|
ln_r1 = math.log(params['r1'])
|
|
self.c3 = 0.
|
|
self.c2 = 1. / params['beta']
|
|
self.c1 = inv_t1 - self.c2 * ln_r1
|
|
|
|
# Linear style conversion chips calibrated with two temp measurements
|
|
class Linear:
|
|
def __init__(self, config, params):
|
|
adc_voltage = config.getfloat('adc_voltage', 5., above=0.)
|
|
slope = (params['t2'] - params['t1']) / (params['v2'] - params['v1'])
|
|
self.gain = adc_voltage * slope
|
|
self.offset = params['t1'] - params['v1'] * slope
|
|
def calc_temp(self, adc):
|
|
return adc * self.gain + self.offset
|
|
def calc_adc(self, temp):
|
|
return (temp - self.offset) / self.gain
|
|
|
|
# Available sensors
|
|
Sensors = {
|
|
"EPCOS 100K B57560G104F": {
|
|
'class': Thermistor, 't1': 25., 'r1': 100000.,
|
|
't2': 150., 'r2': 1641.9, 't3': 250., 'r3': 226.15 },
|
|
"ATC Semitec 104GT-2": {
|
|
'class': Thermistor, 't1': 20., 'r1': 126800.,
|
|
't2': 150., 'r2': 1360., 't3': 300., 'r3': 80.65 },
|
|
"NTC 100K beta 3950": {
|
|
'class': ThermistorBeta, 't1': 25., 'r1': 100000., 'beta': 3950. },
|
|
"AD595": { 'class': Linear, 't1': 25., 'v1': .25, 't2': 300., 'v2': 3.022 },
|
|
}
|
|
|
|
|
|
######################################################################
|
|
# Heater
|
|
######################################################################
|
|
|
|
SAMPLE_TIME = 0.001
|
|
SAMPLE_COUNT = 8
|
|
REPORT_TIME = 0.300
|
|
PWM_CYCLE_TIME = 0.100
|
|
MAX_HEAT_TIME = 5.0
|
|
AMBIENT_TEMP = 25.
|
|
PID_PARAM_BASE = 255.
|
|
|
|
class error(Exception):
|
|
pass
|
|
|
|
class PrinterHeater:
|
|
error = error
|
|
def __init__(self, printer, config):
|
|
self.name = config.section
|
|
sensor_params = config.getchoice('sensor_type', Sensors)
|
|
self.sensor = sensor_params['class'](config, sensor_params)
|
|
self.min_temp = config.getfloat('min_temp', minval=0.)
|
|
self.max_temp = config.getfloat('max_temp', above=self.min_temp)
|
|
self.min_extrude_temp = config.getfloat(
|
|
'min_extrude_temp', 170., minval=self.min_temp, maxval=self.max_temp)
|
|
self.max_power = config.getfloat('max_power', 1., above=0., maxval=1.)
|
|
self.lock = threading.Lock()
|
|
self.last_temp = 0.
|
|
self.last_temp_time = 0.
|
|
self.target_temp = 0.
|
|
algos = {'watermark': ControlBangBang, 'pid': ControlPID}
|
|
algo = config.getchoice('control', algos)
|
|
heater_pin = config.get('heater_pin')
|
|
if algo is ControlBangBang and self.max_power == 1.:
|
|
self.mcu_pwm = pins.setup_pin(printer, 'digital_out', heater_pin)
|
|
else:
|
|
self.mcu_pwm = pins.setup_pin(printer, 'pwm', heater_pin)
|
|
self.mcu_pwm.setup_cycle_time(PWM_CYCLE_TIME)
|
|
self.mcu_pwm.setup_max_duration(MAX_HEAT_TIME)
|
|
self.mcu_adc = pins.setup_pin(printer, 'adc', config.get('sensor_pin'))
|
|
adc_range = [self.sensor.calc_adc(self.min_temp),
|
|
self.sensor.calc_adc(self.max_temp)]
|
|
self.mcu_adc.setup_minmax(SAMPLE_TIME, SAMPLE_COUNT,
|
|
minval=min(adc_range), maxval=max(adc_range))
|
|
self.mcu_adc.setup_adc_callback(REPORT_TIME, self.adc_callback)
|
|
is_fileoutput = self.mcu_adc.get_mcu().is_fileoutput()
|
|
self.can_extrude = self.min_extrude_temp <= 0. or is_fileoutput
|
|
self.control = algo(self, config)
|
|
# pwm caching
|
|
self.next_pwm_time = 0.
|
|
self.last_pwm_value = 0
|
|
def set_pwm(self, read_time, value):
|
|
if self.target_temp <= 0.:
|
|
value = 0.
|
|
if ((read_time < self.next_pwm_time or not self.last_pwm_value)
|
|
and abs(value - self.last_pwm_value) < 0.05):
|
|
# No significant change in value - can suppress update
|
|
return
|
|
pwm_time = read_time + REPORT_TIME + SAMPLE_TIME*SAMPLE_COUNT
|
|
self.next_pwm_time = pwm_time + 0.75 * MAX_HEAT_TIME
|
|
self.last_pwm_value = value
|
|
logging.debug("%s: pwm=%.3f@%.3f (from %.3f@%.3f [%.3f])" % (
|
|
self.name, value, pwm_time,
|
|
self.last_temp, self.last_temp_time, self.target_temp))
|
|
self.mcu_pwm.set_pwm(pwm_time, value)
|
|
def adc_callback(self, read_time, read_value):
|
|
temp = self.sensor.calc_temp(read_value)
|
|
with self.lock:
|
|
self.last_temp = temp
|
|
self.last_temp_time = read_time
|
|
self.can_extrude = (temp >= self.min_extrude_temp)
|
|
self.control.adc_callback(read_time, temp)
|
|
#logging.debug("temp: %.3f %f = %f" % (read_time, read_value, temp))
|
|
# External commands
|
|
def set_temp(self, print_time, degrees):
|
|
if degrees and (degrees < self.min_temp or degrees > self.max_temp):
|
|
raise error("Requested temperature (%.1f) out of range (%.1f:%.1f)"
|
|
% (degrees, self.min_temp, self.max_temp))
|
|
with self.lock:
|
|
self.target_temp = degrees
|
|
def get_temp(self):
|
|
with self.lock:
|
|
return self.last_temp, self.target_temp
|
|
def check_busy(self, eventtime):
|
|
with self.lock:
|
|
return self.control.check_busy(eventtime)
|
|
def start_auto_tune(self, degrees):
|
|
if degrees and (degrees < self.min_temp or degrees > self.max_temp):
|
|
raise error("Requested temperature (%.1f) out of range (%.1f:%.1f)"
|
|
% (degrees, self.min_temp, self.max_temp))
|
|
with self.lock:
|
|
self.control = ControlAutoTune(self, self.control)
|
|
self.target_temp = degrees
|
|
def finish_auto_tune(self, old_control):
|
|
self.control = old_control
|
|
self.target_temp = 0
|
|
|
|
|
|
######################################################################
|
|
# Bang-bang control algo
|
|
######################################################################
|
|
|
|
class ControlBangBang:
|
|
def __init__(self, heater, config):
|
|
self.heater = heater
|
|
self.max_delta = config.getfloat('max_delta', 2.0, above=0.)
|
|
self.heating = False
|
|
def adc_callback(self, read_time, temp):
|
|
if self.heating and temp >= self.heater.target_temp+self.max_delta:
|
|
self.heating = False
|
|
elif not self.heating and temp <= self.heater.target_temp-self.max_delta:
|
|
self.heating = True
|
|
if self.heating:
|
|
self.heater.set_pwm(read_time, self.heater.max_power)
|
|
else:
|
|
self.heater.set_pwm(read_time, 0.)
|
|
def check_busy(self, eventtime):
|
|
return self.heater.last_temp < self.heater.target_temp-self.max_delta
|
|
|
|
|
|
######################################################################
|
|
# Proportional Integral Derivative (PID) control algo
|
|
######################################################################
|
|
|
|
class ControlPID:
|
|
def __init__(self, heater, config):
|
|
self.heater = heater
|
|
self.Kp = config.getfloat('pid_Kp') / PID_PARAM_BASE
|
|
self.Ki = config.getfloat('pid_Ki') / PID_PARAM_BASE
|
|
self.Kd = config.getfloat('pid_Kd') / PID_PARAM_BASE
|
|
self.min_deriv_time = config.getfloat('pid_deriv_time', 2., above=0.)
|
|
imax = config.getfloat('pid_integral_max', heater.max_power, minval=0.)
|
|
self.temp_integ_max = imax / self.Ki
|
|
self.prev_temp = AMBIENT_TEMP
|
|
self.prev_temp_time = 0.
|
|
self.prev_temp_deriv = 0.
|
|
self.prev_temp_integ = 0.
|
|
def adc_callback(self, read_time, temp):
|
|
time_diff = read_time - self.prev_temp_time
|
|
# Calculate change of temperature
|
|
temp_diff = temp - self.prev_temp
|
|
if time_diff >= self.min_deriv_time:
|
|
temp_deriv = temp_diff / time_diff
|
|
else:
|
|
temp_deriv = (self.prev_temp_deriv * (self.min_deriv_time-time_diff)
|
|
+ temp_diff) / self.min_deriv_time
|
|
# Calculate accumulated temperature "error"
|
|
temp_err = self.heater.target_temp - temp
|
|
temp_integ = self.prev_temp_integ + temp_err * time_diff
|
|
temp_integ = max(0., min(self.temp_integ_max, temp_integ))
|
|
# Calculate output
|
|
co = self.Kp*temp_err + self.Ki*temp_integ - self.Kd*temp_deriv
|
|
#logging.debug("pid: %f@%.3f -> diff=%f deriv=%f err=%f integ=%f co=%d" % (
|
|
# temp, read_time, temp_diff, temp_deriv, temp_err, temp_integ, co))
|
|
bounded_co = max(0., min(self.heater.max_power, co))
|
|
self.heater.set_pwm(read_time, bounded_co)
|
|
# Store state for next measurement
|
|
self.prev_temp = temp
|
|
self.prev_temp_time = read_time
|
|
self.prev_temp_deriv = temp_deriv
|
|
if co == bounded_co:
|
|
self.prev_temp_integ = temp_integ
|
|
def check_busy(self, eventtime):
|
|
temp_diff = self.heater.target_temp - self.heater.last_temp
|
|
return abs(temp_diff) > 1. or abs(self.prev_temp_deriv) > 0.1
|
|
|
|
|
|
######################################################################
|
|
# Ziegler-Nichols PID autotuning
|
|
######################################################################
|
|
|
|
TUNE_PID_DELTA = 5.0
|
|
|
|
class ControlAutoTune:
|
|
def __init__(self, heater, old_control):
|
|
self.heater = heater
|
|
self.old_control = old_control
|
|
self.heating = False
|
|
self.peaks = []
|
|
self.peak = 0.
|
|
self.peak_time = 0.
|
|
def adc_callback(self, read_time, temp):
|
|
if self.heating and temp >= self.heater.target_temp:
|
|
self.heating = False
|
|
self.check_peaks()
|
|
elif (not self.heating
|
|
and temp <= self.heater.target_temp - TUNE_PID_DELTA):
|
|
self.heating = True
|
|
self.check_peaks()
|
|
if self.heating:
|
|
self.heater.set_pwm(read_time, self.heater.max_power)
|
|
if temp < self.peak:
|
|
self.peak = temp
|
|
self.peak_time = read_time
|
|
else:
|
|
self.heater.set_pwm(read_time, 0.)
|
|
if temp > self.peak:
|
|
self.peak = temp
|
|
self.peak_time = read_time
|
|
def check_peaks(self):
|
|
self.peaks.append((self.peak, self.peak_time))
|
|
if self.heating:
|
|
self.peak = 9999999.
|
|
else:
|
|
self.peak = -9999999.
|
|
if len(self.peaks) < 4:
|
|
return
|
|
temp_diff = self.peaks[-1][0] - self.peaks[-2][0]
|
|
time_diff = self.peaks[-1][1] - self.peaks[-3][1]
|
|
max_power = self.heater.max_power
|
|
Ku = 4. * (2. * max_power) / (abs(temp_diff) * math.pi)
|
|
Tu = time_diff
|
|
|
|
Kp = 0.6 * Ku
|
|
Ti = 0.5 * Tu
|
|
Td = 0.125 * Tu
|
|
Ki = Kp / Ti
|
|
Kd = Kp * Td
|
|
logging.info("Autotune: raw=%f/%f Ku=%f Tu=%f Kp=%f Ki=%f Kd=%f" % (
|
|
temp_diff, max_power, Ku, Tu,
|
|
Kp * PID_PARAM_BASE, Ki * PID_PARAM_BASE, Kd * PID_PARAM_BASE))
|
|
def check_busy(self, eventtime):
|
|
if self.heating or len(self.peaks) < 12:
|
|
return True
|
|
self.heater.finish_auto_tune(self.old_control)
|
|
return False
|
|
|
|
|
|
######################################################################
|
|
# Tuning information test
|
|
######################################################################
|
|
|
|
class ControlBumpTest:
|
|
def __init__(self, heater, old_control):
|
|
self.heater = heater
|
|
self.old_control = old_control
|
|
self.temp_samples = {}
|
|
self.pwm_samples = {}
|
|
self.state = 0
|
|
def set_pwm(self, read_time, value):
|
|
self.pwm_samples[read_time + 2*REPORT_TIME] = value
|
|
self.heater.set_pwm(read_time, value)
|
|
def adc_callback(self, read_time, temp):
|
|
self.temp_samples[read_time] = temp
|
|
if not self.state:
|
|
self.set_pwm(read_time, 0.)
|
|
if len(self.temp_samples) >= 20:
|
|
self.state += 1
|
|
elif self.state == 1:
|
|
if temp < self.heater.target_temp:
|
|
self.set_pwm(read_time, self.heater.max_power)
|
|
return
|
|
self.set_pwm(read_time, 0.)
|
|
self.state += 1
|
|
elif self.state == 2:
|
|
self.set_pwm(read_time, 0.)
|
|
if temp <= (self.heater.target_temp + AMBIENT_TEMP) / 2.:
|
|
self.dump_stats()
|
|
self.state += 1
|
|
def dump_stats(self):
|
|
out = ["%.3f %.1f %d" % (time, temp, self.pwm_samples.get(time, -1.))
|
|
for time, temp in sorted(self.temp_samples.items())]
|
|
f = open("/tmp/heattest.txt", "wb")
|
|
f.write('\n'.join(out))
|
|
f.close()
|
|
def check_busy(self, eventtime):
|
|
if self.state < 3:
|
|
return True
|
|
self.heater.finish_auto_tune(self.old_control)
|
|
return False
|
|
|
|
def add_printer_objects(printer, config):
|
|
if config.has_section('heater_bed'):
|
|
printer.add_object('heater_bed', PrinterHeater(
|
|
printer, config.getsection('heater_bed')))
|