121 lines
5.4 KiB
Python
121 lines
5.4 KiB
Python
# Support fans that are enabled when temperature exceeds a set threshold
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#
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# Copyright (C) 2016-2018 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import fan
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KELVIN_TO_CELCIUS = -273.15
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MAX_FAN_TIME = 5.0
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AMBIENT_TEMP = 25.
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PID_PARAM_BASE = 255.
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class TemperatureFan:
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def __init__(self, config):
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self.name = config.get_name().split()[1]
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self.printer = config.get_printer()
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self.fan = fan.PrinterFan(config, default_shutdown_speed=1.)
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self.mcu = self.fan.mcu_fan.get_mcu()
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self.min_temp = config.getfloat('min_temp', minval=KELVIN_TO_CELCIUS)
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self.max_temp = config.getfloat('max_temp', above=self.min_temp)
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self.sensor = self.printer.lookup_object('heater').setup_sensor(config)
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self.sensor.setup_minmax(self.min_temp, self.max_temp)
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self.sensor.setup_callback(self.temperature_callback)
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self.speed_delay = self.sensor.get_report_time_delta()
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self.max_speed = config.getfloat('max_speed', 1., above=0., maxval=1.)
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self.min_speed = config.getfloat('min_speed', 0.3, above=0., maxval=1.)
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self.last_temp = 0.
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self.last_temp_time = 0.
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self.target_temp = config.getfloat('target_temp', 40. if self.max_temp > 40. else self.max_temp,
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minval=self.min_temp, maxval=self.max_temp)
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algos = {'watermark': ControlBangBang, 'pid': ControlPID}
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algo = config.getchoice('control', algos)
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self.control = algo(self, config)
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self.next_speed_time = 0.
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self.last_speed_value = 0.
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def set_speed(self, read_time, value):
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if value < self.min_speed:
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value = 0.
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if self.target_temp <= 0.:
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value = 0.
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if ((read_time < self.next_speed_time or not self.last_speed_value)
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and abs(value - self.last_speed_value) < 0.05):
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# No significant change in value - can suppress update
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return
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speed_time = read_time + self.speed_delay
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self.next_speed_time = speed_time + 0.75 * MAX_FAN_TIME
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self.last_speed_value = value
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self.fan.set_speed(speed_time, value)
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def temperature_callback(self, read_time, temp):
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self.last_temp = temp
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self.control.temperature_callback(read_time, temp)
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def stats(self, eventtime):
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return False, '%s: temp=%.1f fan_speed=%.3f' % (
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self.name, self.last_temp, self.last_speed_value)
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######################################################################
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# Bang-bang control algo
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######################################################################
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class ControlBangBang:
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def __init__(self, temperature_fan, config):
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self.temperature_fan = temperature_fan
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self.max_delta = config.getfloat('max_delta', 2.0, above=0.)
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self.heating = False
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def temperature_callback(self, read_time, temp):
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if self.heating and temp >= self.temperature_fan.target_temp+self.max_delta:
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self.heating = False
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elif not self.heating and temp <= self.temperature_fan.target_temp-self.max_delta:
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self.heating = True
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if self.heating:
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self.temperature_fan.set_speed(read_time, 0.)
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else:
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self.temperature_fan.set_speed(read_time, self.temperature_fan.max_speed)
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######################################################################
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# Proportional Integral Derivative (PID) control algo
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######################################################################
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PID_SETTLE_DELTA = 1.
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PID_SETTLE_SLOPE = .1
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class ControlPID:
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def __init__(self, temperature_fan, config):
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self.temperature_fan = temperature_fan
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self.Kp = config.getfloat('pid_Kp') / PID_PARAM_BASE
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self.Ki = config.getfloat('pid_Ki') / PID_PARAM_BASE
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self.Kd = config.getfloat('pid_Kd') / PID_PARAM_BASE
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self.min_deriv_time = config.getfloat('pid_deriv_time', 2., above=0.)
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imax = config.getfloat('pid_integral_max', temperature_fan.max_speed, minval=0.)
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self.temp_integ_max = imax / self.Ki
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self.prev_temp = AMBIENT_TEMP
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self.prev_temp_time = 0.
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self.prev_temp_deriv = 0.
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self.prev_temp_integ = 0.
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def temperature_callback(self, read_time, temp):
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time_diff = read_time - self.prev_temp_time
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# Calculate change of temperature
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temp_diff = temp - self.prev_temp
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if time_diff >= self.min_deriv_time:
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temp_deriv = temp_diff / time_diff
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else:
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temp_deriv = (self.prev_temp_deriv * (self.min_deriv_time-time_diff)
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+ temp_diff) / self.min_deriv_time
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# Calculate accumulated temperature "error"
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temp_err = self.temperature_fan.target_temp - temp
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temp_integ = self.prev_temp_integ + temp_err * time_diff
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temp_integ = max(0., min(self.temp_integ_max, temp_integ))
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# Calculate output
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co = self.Kp*temp_err + self.Ki*temp_integ - self.Kd*temp_deriv
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bounded_co = max(0., min(self.temperature_fan.max_speed, co))
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self.temperature_fan.set_speed(read_time, self.temperature_fan.max_speed - bounded_co)
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# Store state for next measurement
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self.prev_temp = temp
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self.prev_temp_time = read_time
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self.prev_temp_deriv = temp_deriv
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if co == bounded_co:
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self.prev_temp_integ = temp_integ
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def load_config_prefix(config):
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return TemperatureFan(config)
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