diff options
Diffstat (limited to 'klippy/heater.py')
| -rw-r--r-- | klippy/heater.py | 28 |
1 files changed, 22 insertions, 6 deletions
diff --git a/klippy/heater.py b/klippy/heater.py index 7ad2318c..84249a9d 100644 --- a/klippy/heater.py +++ b/klippy/heater.py @@ -9,9 +9,13 @@ import math, logging, threading Sensors = { # Common thermistors and their Steinhart-Hart coefficients "EPCOS 100K B57560G104F": ( + "thermistor", 0.000722136308968056, 0.000216766566488498, 8.92935804531095e-08), "ATC Semitec 104GT-2": ( + "thermistor", 0.000809651054275124, 0.000211636030735685, 7.07420883993973e-08), + # Linear style conversion chips and their gain/offset + "AD595": ("linear", 300.0 / 3.022, 0.), } SAMPLE_TIME = 0.001 @@ -30,8 +34,14 @@ class PrinterHeater: error = error def __init__(self, printer, config): self.name = config.section - self.sensor_c = config.getchoice('sensor_type', Sensors) - self.pullup_r = config.getfloat('pullup_resistor', 4700.) + sensor_params = config.getchoice('sensor_type', Sensors) + self.is_linear_sensor = (sensor_params[0] == 'linear') + if self.is_linear_sensor: + adc_voltage = config.getfloat('adc_voltage', 5.) + self.sensor_coef = sensor_params[1] * adc_voltage, sensor_params[2] + else: + pullup = config.getfloat('pullup_resistor', 4700.) + self.sensor_coef = sensor_params[1:] + (pullup,) self.min_extrude_temp = config.getfloat('min_extrude_temp', 170.) self.min_temp = config.getfloat('min_temp') self.max_temp = config.getfloat('max_temp') @@ -80,21 +90,27 @@ class PrinterHeater: self.mcu_pwm.set_pwm(pwm_time, value) # Temperature calculation def calc_temp(self, adc): - r = self.pullup_r * adc / (1.0 - adc) + if self.is_linear_sensor: + gain, offset = self.sensor_coef + return adc * gain + offset + c1, c2, c3, pullup = self.sensor_coef + r = pullup * adc / (1.0 - adc) ln_r = math.log(r) - c1, c2, c3 = self.sensor_c temp_inv = c1 + c2*ln_r + c3*math.pow(ln_r, 3) return 1.0/temp_inv + KELVIN_TO_CELCIUS def calc_adc(self, temp): if temp is None: return None - c1, c2, c3 = self.sensor_c + if self.is_linear_sensor: + gain, offset = self.sensor_coef + return (temp - offset) / gain + c1, c2, c3, pullup = self.sensor_coef temp -= KELVIN_TO_CELCIUS temp_inv = 1./temp y = (c1 - temp_inv) / (2*c3) x = math.sqrt(math.pow(c2 / (3.*c3), 3.) + math.pow(y, 2.)) r = math.exp(math.pow(x-y, 1./3.) - math.pow(x+y, 1./3.)) - return r / (self.pullup_r + r) + return r / (pullup + r) def adc_callback(self, read_time, read_value): temp = self.calc_temp(read_value) with self.lock: |