beta:3950 thermistor table for marlin
March 8, 2014 11 Comments
here’s the thermistor table for the thermistors with a beta of 3950, 100k ohm type. These can usually be found for really cheap on ebay and such, but finding the table for marlin firmware is a bit difficult so here it is, just replace type 8 with this code in thermistortables.h.
#if (THERMISTORHEATER_0 == 8) || (THERMISTORHEATER_1 == 8) || (THERMISTORHEATER_2 == 8) || (THERMISTORBED == 8) // QU-BD silicone bed QWG-104F-3950 thermistor
const short temptable_8[][2] PROGMEM = {
{1*OVERSAMPLENR, 938},
{31*OVERSAMPLENR, 314},
{41*OVERSAMPLENR, 290},
{51*OVERSAMPLENR, 272},
{61*OVERSAMPLENR, 258},
{71*OVERSAMPLENR, 247},
{81*OVERSAMPLENR, 237},
{91*OVERSAMPLENR, 229},
{101*OVERSAMPLENR, 221},
{111*OVERSAMPLENR, 215},
{121*OVERSAMPLENR, 209},
{131*OVERSAMPLENR, 204},
{141*OVERSAMPLENR, 199},
{151*OVERSAMPLENR, 195},
{161*OVERSAMPLENR, 190},
{171*OVERSAMPLENR, 187},
{181*OVERSAMPLENR, 183},
{191*OVERSAMPLENR, 179},
{201*OVERSAMPLENR, 176},
{221*OVERSAMPLENR, 170},
{241*OVERSAMPLENR, 165},
{261*OVERSAMPLENR, 160},
{281*OVERSAMPLENR, 155},
{301*OVERSAMPLENR, 150},
{331*OVERSAMPLENR, 144},
{361*OVERSAMPLENR, 139},
{391*OVERSAMPLENR, 133},
{421*OVERSAMPLENR, 128},
{451*OVERSAMPLENR, 123},
{491*OVERSAMPLENR, 117},
{531*OVERSAMPLENR, 111},
{571*OVERSAMPLENR, 105},
{611*OVERSAMPLENR, 100},
{641*OVERSAMPLENR, 95},
{681*OVERSAMPLENR, 90},
{711*OVERSAMPLENR, 85},
{751*OVERSAMPLENR, 79},
{791*OVERSAMPLENR, 72},
{811*OVERSAMPLENR, 69},
{831*OVERSAMPLENR, 65},
{871*OVERSAMPLENR, 57},
{881*OVERSAMPLENR, 55},
{901*OVERSAMPLENR, 51},
{921*OVERSAMPLENR, 45},
{941*OVERSAMPLENR, 39},
{971*OVERSAMPLENR, 28},
{981*OVERSAMPLENR, 23},
{991*OVERSAMPLENR, 17},
{1001*OVERSAMPLENR, 9},
{1021*OVERSAMPLENR, -27}
};
#endif
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I just made a pull request to have this thermistor available inside the firwmare as thermistor 11
cool, Im excited to see if it does go through and becomes part of the firmware.
The pull request was merged so it should be available right now!
I saw, thanks! I was excited to see that the other day when I updated the firmware on my prusa.
Thanks big time for your work. Testing it right now!
On my side using a chinese wireless thermometer it’s fine.
I’m using them for quite some time now and i’m preatty happy with your table 😉
thank you for using it and adding it to the official marlin firmware.
Also sorry for not responding back fred, didnt see any new messages come through.
I have seen mention of a 4.7k ohm pull-up resistor when referring to thermistors. In your circuit, did you place a 4.7k ohm resistor in series with this thermistor when printing? Or, as the name suggests, is the pull-up placed between one leg of the thermistor and the voltage source (i.e. 12v or 5v)?
The resistor value is set for the electronics you use with it, like with what I use, a gen7 board, it uses a 4.7k resistor as a pull up resistor to 5v, so that the resistor/thermistor acts as a voltage divider. Various setups in the past have used various values, like some thermistors have used 10k, some was 1k, etc. It just dependended on the thermistor used and the level of precision that they wanted. It was mainly dependant on the value of the thermistor, some was 10k, most is 100k, some are 50k, etc, so the pull up resistor is just dependant on the value of the thermistor.
mainly all electronics that you find uses 4.7k as a generic value, so you wouldnt really have to worry about it unless your designing custom electronics, and if you were using this thermistor, just stick with the 4.7k one.
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