No no, PI(D) is just a kind of control loop algorithm, it has nothing to do with coil material. The P and I coefficients describe how fast the target (set temp) will be reached and how fast it will stabilize (including amount of ripple etc) You should enable it in all cases as the stock TC algo in these devices is just plain awful.
TI think you are mixing it with TCR vs TFR (ie. a single coeff for material vs a plot with a points list), and indeed TFR should be preferred if possible. And indeed again, we don't have such a TFR curve for the Splinter heater (but I've been successfully using the 316 and 316L ones with my iHeat for instance)
We just know the RBT heater is made of some kind of stainless steel grade but that's all. So it would make sense to tweak a 304, 316, 317 or 340 curve as a starting point.
Thanks! You are correct, I had TCR and PID conflated. TCR and TFR are the two methods of getting the temperature from the coil. TCR is a linear plot from a baseline whereas TFR is a plotted curve that you input. PID is the regulator algorithm that turns on and off the coil at a given wattage.
R = Range.. this is the % of the target temp that you wish to reach that turns on PID regulation. I would just leave this at 0% so PI regulation is always on. P is how much power you want to ramp up in Mw/C per degree C and I = mw/C/seconds is the power per degree over time. A high P value will put in a lot of power. The I value is how fast you want to get there. These can be tweaked to get a favorable ramp...
In order for the PI regulator to work, it has to have a good TCR or TFR reading. It seems to me that TFR is more intuitive than TCR. TCR is a value that is used by multiplying the base resistance by that TCR.
Whereas with TFR, we can create our own curve. I assume the 1.0 factor is the base resistance and as it increase with heat, it uses the TFR table to get the temperature. I don't have a temp gun, but it seems to me I could take the temp while simultaneously recording the resistance. This might be hard to do though.