mirror of
				https://github.com/Klipper3d/klipper.git
				synced 2025-10-31 02:15:52 +01:00 
			
		
		
		
	Add in support for the "TDK NTCG104LH104JT1" thermistor. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
		
			
				
	
	
		
			134 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			134 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| # Temperature measurements with thermistors
 | |
| #
 | |
| # Copyright (C) 2016-2019  Kevin O'Connor <kevin@koconnor.net>
 | |
| #
 | |
| # This file may be distributed under the terms of the GNU GPLv3 license.
 | |
| import math, logging
 | |
| from . import adc_temperature
 | |
| 
 | |
| KELVIN_TO_CELSIUS = -273.15
 | |
| 
 | |
| # Analog voltage to temperature converter for thermistors
 | |
| class Thermistor:
 | |
|     def __init__(self, pullup, inline_resistor):
 | |
|         self.pullup = pullup
 | |
|         self.inline_resistor = inline_resistor
 | |
|         self.c1 = self.c2 = self.c3 = 0.
 | |
|     def setup_coefficients(self, t1, r1, t2, r2, t3, r3, name=""):
 | |
|         # Calculate Steinhart-Hart coefficents from temp measurements.
 | |
|         # Arrange samples as 3 linear equations and solve for c1, c2, and c3.
 | |
|         inv_t1 = 1. / (t1 - KELVIN_TO_CELSIUS)
 | |
|         inv_t2 = 1. / (t2 - KELVIN_TO_CELSIUS)
 | |
|         inv_t3 = 1. / (t3 - KELVIN_TO_CELSIUS)
 | |
|         ln_r1 = math.log(r1)
 | |
|         ln_r2 = math.log(r2)
 | |
|         ln_r3 = math.log(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))
 | |
|         if self.c3 <= 0.:
 | |
|             beta = ln_r13 / inv_t13
 | |
|             logging.warn("Using thermistor beta %.3f in heater %s", beta, name)
 | |
|             self.setup_coefficients_beta(t1, r1, beta)
 | |
|             return
 | |
|         self.c2 = (inv_t12 - self.c3 * ln3_r12) / ln_r12
 | |
|         self.c1 = inv_t1 - self.c2 * ln_r1 - self.c3 * ln3_r1
 | |
|     def setup_coefficients_beta(self, t1, r1, beta):
 | |
|         # Calculate equivalent Steinhart-Hart coefficents from beta
 | |
|         inv_t1 = 1. / (t1 - KELVIN_TO_CELSIUS)
 | |
|         ln_r1 = math.log(r1)
 | |
|         self.c3 = 0.
 | |
|         self.c2 = 1. / beta
 | |
|         self.c1 = inv_t1 - self.c2 * ln_r1
 | |
|     def calc_temp(self, adc):
 | |
|         # Calculate temperature from adc
 | |
|         adc = max(.00001, min(.99999, adc))
 | |
|         r = self.pullup * adc / (1.0 - adc)
 | |
|         ln_r = math.log(r - self.inline_resistor)
 | |
|         inv_t = self.c1 + self.c2 * ln_r + self.c3 * ln_r**3
 | |
|         return 1.0/inv_t + KELVIN_TO_CELSIUS
 | |
|     def calc_adc(self, temp):
 | |
|         # Calculate adc reading from a temperature
 | |
|         if temp <= KELVIN_TO_CELSIUS:
 | |
|             return 1.
 | |
|         inv_t = 1. / (temp - KELVIN_TO_CELSIUS)
 | |
|         if self.c3:
 | |
|             # Solve for ln_r using Cardano's formula
 | |
|             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) + self.inline_resistor
 | |
|         return r / (self.pullup + r)
 | |
| 
 | |
| # Create an ADC converter with a thermistor
 | |
| def PrinterThermistor(config, params):
 | |
|     pullup = config.getfloat('pullup_resistor', 4700., above=0.)
 | |
|     inline_resistor = config.getfloat('inline_resistor', 0., minval=0.)
 | |
|     thermistor = Thermistor(pullup, inline_resistor)
 | |
|     if 'beta' in params:
 | |
|         thermistor.setup_coefficients_beta(
 | |
|             params['t1'], params['r1'], params['beta'])
 | |
|     else:
 | |
|         thermistor.setup_coefficients(
 | |
|             params['t1'], params['r1'], params['t2'], params['r2'],
 | |
|             params['t3'], params['r3'], name=config.get_name())
 | |
|     return adc_temperature.PrinterADCtoTemperature(config, thermistor)
 | |
| 
 | |
| # Custom defined thermistors from the config file
 | |
| class CustomThermistor:
 | |
|     def __init__(self, config):
 | |
|         self.name = " ".join(config.get_name().split()[1:])
 | |
|         t1 = config.getfloat("temperature1", minval=KELVIN_TO_CELSIUS)
 | |
|         r1 = config.getfloat("resistance1", minval=0.)
 | |
|         beta = config.getfloat("beta", None, above=0.)
 | |
|         if beta is not None:
 | |
|             self.params = {'t1': t1, 'r1': r1, 'beta': beta}
 | |
|             return
 | |
|         t2 = config.getfloat("temperature2", minval=KELVIN_TO_CELSIUS)
 | |
|         r2 = config.getfloat("resistance2", minval=0.)
 | |
|         t3 = config.getfloat("temperature3", minval=KELVIN_TO_CELSIUS)
 | |
|         r3 = config.getfloat("resistance3", minval=0.)
 | |
|         (t1, r1), (t2, r2), (t3, r3) = sorted([(t1, r1), (t2, r2), (t3, r3)])
 | |
|         self.params = {'t1': t1, 'r1': r1, 't2': t2, 'r2': r2,
 | |
|                        't3': t3, 'r3': r3}
 | |
|     def create(self, config):
 | |
|         return PrinterThermistor(config, self.params)
 | |
| 
 | |
| # Default sensors
 | |
| Sensors = {
 | |
|     "EPCOS 100K B57560G104F": {
 | |
|         't1': 25., 'r1': 100000., 't2': 150., 'r2': 1641.9,
 | |
|         't3': 250., 'r3': 226.15 },
 | |
|     "ATC Semitec 104GT-2": {
 | |
|         't1': 20., 'r1': 126800., 't2': 150., 'r2': 1360.,
 | |
|         't3': 300., 'r3': 80.65 },
 | |
|     "SliceEngineering 450": {
 | |
|         't1': 25., 'r1': 500000., 't2': 200., 'r2': 3734.,
 | |
|         't3': 400., 'r3': 240. },
 | |
|     "TDK NTCG104LH104JT1": {
 | |
|         't1': 25., 'r1': 100000., 't2': 50., 'r2': 31230.,
 | |
|         't3': 125., 'r3': 2066. },
 | |
|     "NTC 100K beta 3950": { 't1': 25., 'r1': 100000., 'beta': 3950. },
 | |
|     "Honeywell 100K 135-104LAG-J01": { 't1': 25., 'r1': 100000., 'beta': 3974.},
 | |
|     "NTC 100K MGB18-104F39050L32": { 't1': 25., 'r1': 100000., 'beta': 4100. },
 | |
| }
 | |
| 
 | |
| def load_config(config):
 | |
|     # Register default thermistor types
 | |
|     pheaters = config.get_printer().load_object(config, "heaters")
 | |
|     for sensor_type, params in Sensors.items():
 | |
|         func = (lambda config, params=params: PrinterThermistor(config, params))
 | |
|         pheaters.add_sensor_factory(sensor_type, func)
 | |
| 
 | |
| def load_config_prefix(config):
 | |
|     thermistor = CustomThermistor(config)
 | |
|     pheaters = config.get_printer().load_object(config, "heaters")
 | |
|     pheaters.add_sensor_factory(thermistor.name, thermistor.create)
 |