Extended range above 250C. (Operating range states up to 300C)

Marlin/thermistortables.h

 };
 #endif
 #if (THERMISTORHEATER_0 == 2) || (THERMISTORHEATER_1 == 2) || (THERMISTORHEATER_2 == 2) || (THERMISTORBED == 2) //200k bed thermistor
-const short temptable_2[][2] PROGMEM = {
-   {1*OVERSAMPLENR, 848},
-   {54*OVERSAMPLENR, 275},
-   {107*OVERSAMPLENR, 228},
-   {160*OVERSAMPLENR, 202},
-   {213*OVERSAMPLENR, 185},
-   {266*OVERSAMPLENR, 171},
-   {319*OVERSAMPLENR, 160},
-   {372*OVERSAMPLENR, 150},
-   {425*OVERSAMPLENR, 141},
-   {478*OVERSAMPLENR, 133},
-   {531*OVERSAMPLENR, 125},
-   {584*OVERSAMPLENR, 118},
-   {637*OVERSAMPLENR, 110},
-   {690*OVERSAMPLENR, 103},
-   {743*OVERSAMPLENR, 95},
-   {796*OVERSAMPLENR, 86},
-   {849*OVERSAMPLENR, 77},
-   {902*OVERSAMPLENR, 65},
-   {955*OVERSAMPLENR, 49},
-   {1008*OVERSAMPLENR, 17},
-   {1020*OVERSAMPLENR, 0} //safety
+   const short temptable_2[][2] PROGMEM = {
+//200k ATC Semitec 204GT-2
+//Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
+// Calculated using 4.7kohm pullup, voltage divider math, and manufacturer provided temp/resistance
+   {30*OVERSAMPLENR, 300},
+   {34*OVERSAMPLENR, 290},
+   {39*OVERSAMPLENR, 280},
+   {46*OVERSAMPLENR, 270},
+   {53*OVERSAMPLENR, 260},
+   {63*OVERSAMPLENR, 250},
+   {74*OVERSAMPLENR, 240},
+   {87*OVERSAMPLENR, 230},
+   {104*OVERSAMPLENR, 220},
+   {124*OVERSAMPLENR, 210},
+   {148*OVERSAMPLENR, 200},
+   {176*OVERSAMPLENR, 190},
+   {211*OVERSAMPLENR, 180},
+   {252*OVERSAMPLENR, 170},
+   {301*OVERSAMPLENR, 160},
+   {357*OVERSAMPLENR, 150},
+   {420*OVERSAMPLENR, 140},
+   {489*OVERSAMPLENR, 130},
+   {562*OVERSAMPLENR, 120},
+   {636*OVERSAMPLENR, 110},
+   {708*OVERSAMPLENR, 100},
+   {775*OVERSAMPLENR, 90},
+   {835*OVERSAMPLENR, 80},
+   {884*OVERSAMPLENR, 70},
+   {924*OVERSAMPLENR, 60},
+   {955*OVERSAMPLENR, 50},
+   {977*OVERSAMPLENR, 40},
+   {993*OVERSAMPLENR, 30},
+   {1004*OVERSAMPLENR, 20},
+   {1012*OVERSAMPLENR, 10},
+   {1016*OVERSAMPLENR, 0},
 };
 
 #endif