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make use of power operator

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This commit is contained in:
Steffen Vogel 2015-01-06 10:28:43 +01:00
parent 4e02aff9b5
commit f7e65935fb
1 changed files with 4 additions and 6 deletions
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10
Marlin/scripts/createTemperatureLookupMarlin.py
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@ -26,7 +26,7 @@ import getopt
ZERO = 273.15 # zero point of Kelvin scale ZERO = 273.15 # zero point of Kelvin scale
VADC = 5 # ADC voltage VADC = 5 # ADC voltage
VCC = 5 # supply voltage VCC = 5 # supply voltage
ARES = pow(2,10) # 10 Bit ADC resolution ARES = 2**10 # 10 Bit ADC resolution
VSTEP = VADC / ARES # ADC voltage resolution VSTEP = VADC / ARES # ADC voltage resolution
TMIN = 0 # lowest temperature in table TMIN = 0 # lowest temperature in table
TMAX = 350 # highest temperature in table TMAX = 350 # highest temperature in table
@ -43,8 +43,6 @@ class Thermistor:
x = (y2 - y1) / (l2 - l1) x = (y2 - y1) / (l2 - l1)
y = (y3 - y1) / (l3 - l1) y = (y3 - y1) / (l3 - l1)
c = (y - x) / ((l3 - l2) * (l1 + l2 + l3)) c = (y - x) / ((l3 - l2) * (l1 + l2 + l3))
b = x - c * (pow(l1,2) + pow(l2,2) + l1*l2)
a = y1 - (b + pow(l1,2)*c)*l1
self.c1 = a # Steinhart-Hart coefficients self.c1 = a # Steinhart-Hart coefficients
self.c2 = b self.c2 = b
self.c3 = c self.c3 = c
@ -67,14 +65,14 @@ class Thermistor:
def temp(self, adc): def temp(self, adc):
"Convert ADC reading into a temperature in Celcius" "Convert ADC reading into a temperature in Celcius"
l = log(self.resist(adc)) l = log(self.resist(adc))
Tinv = self.c1 + self.c2*l + self.c3*pow(l,3) # inverse temperature Tinv = self.c1 + self.c2*l + self.c3* l**3) # inverse temperature
return (1/Tinv) - ZERO # temperature return (1/Tinv) - ZERO # temperature
def adc(self, temp): def adc(self, temp):
"Convert temperature into a ADC reading" "Convert temperature into a ADC reading"
x = (self.c1 - (1.0 / (temp+ZERO))) / (2*self.c3) x = (self.c1 - (1.0 / (temp+ZERO))) / (2*self.c3)
y = sqrt(pow(self.c2 / (3*self.c3),3) + pow(x,2)) y = sqrt((self.c2 / (3*self.c3)**3 + x**2)
r = exp(pow(y-x,1.0/3) - pow(y+x,1.0/3)) # resistance of thermistor r = exp((y-x)**(1.0/3) - (y+x)**(1.0/3))
return (r / (self.rp + r)) * ARES return (r / (self.rp + r)) * ARES
def main(argv): def main(argv):