here is something i wrote elsewhere in the forum .
So you want to see what this “TC” temp control is all about?
This is my take on the temp control, I have come to these conclusions after being an early adopter with the first edition dna40, sx350j, and dna200. Rather than discuss any board at length this more about the commonalities with temp limiting. Notice I said temp limiting and not temp control. The reason being, what vapers refer to as temp control is not control at all. It now can mimic control but it is really a series of ceilings preventing you from getting the coil over a predestined temperature or the mod to fire over a predetermined power output. It is not a thermostat, nor designed to hold it at temperature, only to not cross the temperature set.
Currently there are 3 metals commonly used for Temp Limiting. New metals get experimented with and become fads with this technology as often as shoes get popular. At the time of this writing the three primary metals are NI200. Titanium, and SS. NI200 is the hardest to work with but yields the most consistent results from the board. Titaniu, is highly popular but in my opinion can yield rather inconsistent results and was left with rumors of less than healthy output should it get to hot. (temp limiting?) stainless steel, is my personal favorite because of its ease of use, benign health effects and proficiency.
When buying a TC mod the 2 features to make sure the mod has is software upgradable, and the ability to load in your own tcr value.
What is a tcr value? TCR is the basis of temp control. Essentially, TC works by using metals whose resistance increases in a linear fashion as the temperature increases. In other words resistance goes up at a constant rate as temperature goes up. The board uses its starting temp and resistance; then, figures out the change in resistance, and, uses that to factor the current temperature. It then regulates the temperature by backing down the power output and monitoring the resistance.
The nature of the technology leads it to be a little bit finicky at first; and, while each model does thing marginally different a major constant are the things that it is finicky about. Primarily, since tc relies on the resistance change with temp, and that these changes are so minute, good, clean, solid connections are a must. Additionally, Contact coils do not work right- contact coils "work" in non tc mode due to the oxidation buildup on kanthal a1, but since tc relies on non-oxidizing coil material, you don't get the isolation, and have wildly fluctuating coils. This is especially noticeable with ni200 and why many early adopter went on a search for something more user friendly. Its resistance is so low and the metal itself is so soft that it became very troublesome to use. Stainless however is very similar to build with as Kanthal and the resistance is high enough to be used in power mode
On many mods, you need to “pair’” your atomizer with the mod in order to give the mod a baseline resistance from whence to start. This is KEY as this is the very basis of TC any change in the resistance will throw the calculation of and lead to a bad vape. Even body temperature, it is this reason that before pairing the mod, and after the build, set the atomizer and mod to the side for about 10-15 minutes and let them both come to the same temperature. Then screw on your atty and lock in the resistance.
Mods with a loadable tcr value will have a place where you can plug in a number generally starting around the third place after the decimal. This chart has some of the more commonly used tcr values.
www.steam-engine.org has the tcr values for most metals available with a tcr value associated to them. In the event that you are using a dna2oo steam engine also has downloadable .csv files available as well. These .csv files are exact charts for the tcr of a given metal that allow the DNA board to be a little more accurate.
I hope this information gives you a fair bearing on using TC and helps in some way should you have any injuries’ please let us know