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heater: Support max_power setting for heaters

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Change the mcu PWM value from an integer (0-255) to a float (0. - 1.).
Add support for limiting the maximum power (as measured over a
sufficiently long duration) to a particular heater.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
2016-08-25 11:24:18 -04:00
parent 54002c4391
commit f53897758d
4 changed files with 40 additions and 29 deletions
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46
klippy/heater.py
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@@ -19,7 +19,7 @@ REPORT_TIME = 0.300
KELVIN_TO_CELCIUS = -273.15
MAX_HEAT_TIME = 5.0
AMBIENT_TEMP = 25.
PWM_MAX = 255
PID_PARAM_BASE = 255.
class error(Exception):
pass
@@ -35,6 +35,7 @@ class PrinterHeater:
self.min_extrude_temp = config.getfloat('min_extrude_temp', 170.)
self.min_temp = self.config.getfloat('min_temp')
self.max_temp = self.config.getfloat('max_temp')
self.max_power = max(0., min(1., self.config.getfloat('max_power', 1.)))
self.can_extrude = (self.min_extrude_temp <= 0.)
self.lock = threading.Lock()
self.last_temp = 0.
@@ -49,7 +50,7 @@ class PrinterHeater:
algo = self.config.getchoice('control', algos)
heater_pin = self.config.get('heater_pin')
thermistor_pin = self.config.get('thermistor_pin')
if algo is ControlBangBang:
if algo is ControlBangBang and self.max_power == 1.:
self.mcu_pwm = self.printer.mcu.create_digital_out(
heater_pin, MAX_HEAT_TIME)
else:
@@ -69,7 +70,7 @@ class PrinterHeater:
if self.target_temp <= 0.:
return
if (read_time < self.next_pwm_time
and abs(value - self.last_pwm_value) < 15):
and abs(value - self.last_pwm_value) < 0.05):
return
elif not self.last_pwm_value and (
self.target_temp <= 0. or read_time < self.next_pwm_time):
@@ -77,7 +78,7 @@ class PrinterHeater:
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=%d@%.3f (from %.3f@%.3f [%.3f])" % (
logging.debug("%s: pwm=%.3f@%.3f (from %.3f@%.3f [%.3f])" % (
self.config.section, value, pwm_time,
self.last_temp, self.last_temp_time, self.target_temp))
self.mcu_pwm.set_pwm(pwm_time, value)
@@ -139,9 +140,9 @@ class ControlBangBang:
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, PWM_MAX)
self.heater.set_pwm(read_time, self.heater.max_power)
else:
self.heater.set_pwm(read_time, 0)
self.heater.set_pwm(read_time, 0.)
def check_busy(self, eventtime):
return self.heater.last_temp < self.heater.target_temp-self.max_delta
@@ -153,11 +154,11 @@ class ControlBangBang:
class ControlPID:
def __init__(self, heater, config):
self.heater = heater
self.Kp = config.getfloat('pid_Kp')
self.Ki = config.getfloat('pid_Ki')
self.Kd = config.getfloat('pid_Kd')
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.)
imax = config.getint('pid_integral_max', PWM_MAX)
imax = config.getfloat('pid_integral_max', heater.max_power)
self.temp_integ_max = imax / self.Ki
self.prev_temp = AMBIENT_TEMP
self.prev_temp_time = 0.
@@ -177,10 +178,10 @@ class ControlPID:
temp_integ = self.prev_temp_integ + temp_err * time_diff
temp_integ = max(0., min(self.temp_integ_max, temp_integ))
# Calculate output
co = int(self.Kp*temp_err + self.Ki*temp_integ - self.Kd*temp_deriv)
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(PWM_MAX, 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
@@ -216,12 +217,12 @@ class ControlAutoTune:
self.heating = True
self.check_peaks()
if self.heating:
self.heater.set_pwm(read_time, PWM_MAX)
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)
self.heater.set_pwm(read_time, 0.)
if temp > self.peak:
self.peak = temp
self.peak_time = read_time
@@ -235,8 +236,8 @@ class ControlAutoTune:
return
temp_diff = self.peaks[-1][0] - self.peaks[-2][0]
time_diff = self.peaks[-1][1] - self.peaks[-3][1]
pwm_diff = PWM_MAX - 0
Ku = 4. * (2. * pwm_diff) / (abs(temp_diff) * math.pi)
max_power = self.heater.max_power
Ku = 4. * (2. * max_power) / (abs(temp_diff) * math.pi)
Tu = time_diff
Kp = 0.6 * Ku
@@ -244,8 +245,9 @@ class ControlAutoTune:
Td = 0.125 * Tu
Ki = Kp / Ti
Kd = Kp * Td
logging.info("Autotune: raw=%f/%d Ku=%f Tu=%f Kp=%f Ki=%f Kd=%f" % (
temp_diff, pwm_diff, Ku, Tu, Kp, Ki, Kd))
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
@@ -271,17 +273,17 @@ class ControlBumpTest:
def adc_callback(self, read_time, temp):
self.temp_samples[read_time] = temp
if not self.state:
self.set_pwm(read_time, 0)
self.set_pwm(read_time, 0.)
if len(self.temp_samples) >= 20:
self.state += 1
elif self.state == 1:
if temp < self.target_temp:
self.set_pwm(read_time, PWM_MAX)
self.set_pwm(read_time, self.heater.max_power)
return
self.set_pwm(read_time, 0)
self.set_pwm(read_time, 0.)
self.state += 1
elif self.state == 2:
self.set_pwm(read_time, 0)
self.set_pwm(read_time, 0.)
if temp <= (self.target_temp + AMBIENT_TEMP) / 2.:
self.dump_stats()
self.state += 1