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@ -54,9 +54,25 @@ class Thermistor: |
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self.c2 = c2 |
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self.c3 = c3 |
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def res(self,adc): |
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"Convert ADC reading into a resolution" |
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res = self.temp(adc)-self.temp(adc+1) |
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return res |
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def v(self,adc): |
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"Convert ADC reading into a Voltage" |
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v = adc * self.vadc / (1024 ) # convert the 10 bit ADC value to a voltage |
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return v |
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def r(self,adc): |
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"Convert ADC reading into a resistance in Ohms" |
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v = adc * self.vadc / (1024 ) # convert the 10 bit ADC value to a voltage |
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r = self.rp * v / (self.vcc - v) # resistance of thermistor |
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return r |
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def temp(self,adc): |
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"Convert ADC reading into a temperature in Celcius" |
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v = adc * self.vadc / (1024 * 16) # convert the 10 bit ADC value to a voltage |
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v = adc * self.vadc / (1024 ) # convert the 10 bit ADC value to a voltage |
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r = self.rp * v / (self.vcc - v) # resistance of thermistor |
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lnr = log(r) |
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Tinv = self.c1 + (self.c2*lnr) + (self.c3*pow(lnr,3)) |
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@ -67,7 +83,7 @@ class Thermistor: |
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y = (self.c1 - (1/(temp+273.15))) / (2*self.c3) |
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x = sqrt(pow(self.c2 / (3*self.c3),3) + pow(y,2)) |
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r = exp(pow(x-y,1.0/3) - pow(x+y,1.0/3)) # resistance of thermistor |
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return (r / (self.rp + r)) * (1024*16) |
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return (r / (self.rp + r)) * (1024) |
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def main(argv): |
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@ -107,7 +123,7 @@ def main(argv): |
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elif opt == "--num-temps": |
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num_temps = int(arg) |
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max_adc = (1024 * 16) - 1 |
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max_adc = (1024 ) - 1 |
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min_temp = 0 |
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max_temp = 350 |
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increment = int(max_adc/(num_temps-1)); |
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@ -118,17 +134,18 @@ def main(argv): |
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temps = range(max_temp, min_temp + tmp, tmp); |
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print "// Thermistor lookup table for Marlin" |
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print "// ./createTemperatureLookup.py --rp=%s --t1=%s:%s --t2=%s:%s --t3=%s:%s --num-temps=%s" % (rp, t1, r1, t2, r2, t3, r3, num_temps) |
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print "#define NUMTEMPS %s" % (len(temps)) |
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print "short temptable[NUMTEMPS][2] = {" |
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print "// ./createTemperatureLookupMarlin.py --rp=%s --t1=%s:%s --t2=%s:%s --t3=%s:%s --num-temps=%s" % (rp, t1, r1, t2, r2, t3, r3, num_temps) |
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print "// Steinhart-Hart Coefficients: %.15g, %.15g, %.15g " % (t.c1, t.c2, t.c3) |
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print "//#define NUMTEMPS %s" % (len(temps)) |
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print "const short temptable[NUMTEMPS][2] PROGMEM = {" |
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counter = 0 |
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for temp in temps: |
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counter = counter +1 |
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if counter == len(temps): |
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print " {%s, %s}" % (int(t.adc(temp)), temp) |
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print " {(short)(%.2f*OVERSAMPLENR), %s} // v=%s r=%s res=%s C/count" % ((t.adc(temp)), temp, t.v(t.adc(temp)), t.r(t.adc(temp)),t.res(t.adc(temp))) |
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else: |
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print " {%s, %s}," % (int(t.adc(temp)), temp) |
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print " {(short)(%.2f*OVERSAMPLENR), %s}, // v=%s r=%s res=%s C/count" % ((t.adc(temp)), temp, t.v(t.adc(temp)), t.r(t.adc(temp)),t.res(t.adc(temp))) |
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print "};" |
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def usage(): |
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