Public Member Functions
def	__init__ (self, rp, t1, r1, t2, r2, t3, r3)

def	resol (self, adc)

def	voltage (self, adc)

def	resist (self, adc)

def	temp (self, adc)

def	adc (self, temp)

Public Attributes
	c1

	c2

	c3

	rp

Constructor & Destructor Documentation

◆ init()

def createTemperatureLookupMarlin.Thermistor.__init__	(	self,
		rp,
		t1,
		r1,
		t2,
		r2,
		t3,
		r3
	)

     def __init__(self, rp, t1, r1, t2, r2, t3, r3):
         l1 = log(r1)
         l2 = log(r2)
         l3 = log(r3)
         y1 = 1.0 / (t1 + ZERO)              # adjust scale
         y2 = 1.0 / (t2 + ZERO)
         y3 = 1.0 / (t3 + ZERO)
         x = (y2 - y1) / (l2 - l1)
         y = (y3 - y1) / (l3 - l1)
         c = (y - x) / ((l3 - l2) * (l1 + l2 + l3))
         b = x - c * (l1**2 + l2**2 + l1*l2)
         a = y1 - (b + l1**2 *c)*l1
  
         if c < 0:
             print("//////////////////////////////////////////////////////////////////////////////////////")
             print("// WARNING: negative coefficient 'c'! Something may be wrong with the measurements! //")
             print("//////////////////////////////////////////////////////////////////////////////////////")
             c = -c
         self.c1 = a                         # Steinhart-Hart coefficients
         self.c2 = b
         self.c3 = c
         self.rp = rp                        # pull-up resistance
  

Member Function Documentation

◆ resol()

def createTemperatureLookupMarlin.Thermistor.resol	(	self,
		adc
	)

     def resol(self, adc):
         "Convert ADC reading into a resolution"
         res = self.temp(adc)-self.temp(adc+1)
         return res
  

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◆ voltage()

def createTemperatureLookupMarlin.Thermistor.voltage	(	self,
		adc
	)

     def voltage(self, adc):
         "Convert ADC reading into a Voltage"
         return adc * VSTEP                     # convert the 10 bit ADC value to a voltage
  

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◆ resist()

def createTemperatureLookupMarlin.Thermistor.resist	(	self,
		adc
	)

     def resist(self, adc):
         "Convert ADC reading into a resistance in Ohms"
         r = self.rp * self.voltage(adc) / (VCC - self.voltage(adc)) # resistance of thermistor
         return r
  

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◆ temp()

def createTemperatureLookupMarlin.Thermistor.temp	(	self,
		adc
	)

     def temp(self, adc):
         "Convert ADC reading into a temperature in Celcius"
         l = log(self.resist(adc))
         Tinv = self.c1 + self.c2*l + self.c3* l**3 # inverse temperature
         return (1/Tinv) - ZERO              # temperature
  

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◆ adc()

def createTemperatureLookupMarlin.Thermistor.adc	(	self,
		temp
	)

     def adc(self, temp):
         "Convert temperature into a ADC reading"
         x = (self.c1 - (1.0 / (temp+ZERO))) / (2*self.c3)
         y = sqrt((self.c2 / (3*self.c3))**3 + x**2)
         r = exp((y-x)**(1.0/3) - (y+x)**(1.0/3))
         return (r / (self.rp + r)) * ARES
  