The ptc and 22 ohms resistor are part of divider, and thats the problem, like anything else that introduces a voltage drop, it limits the lower point of adc reads, and because thermistor is lower side, lower voltages are where temperatures are read. Thats why i didnt like to change that.
Let me make a scenario. Ppls copy paste tables, someone copies a not shifted table, that means system gets a maximum value after which all higher temps wont produce higher readings coz voltage cant decrease any lower. For examples this with a non-shifted table will read a max temp of say 250C and when temp will be 350, it will still be read as 250C. Why am i only one thinking thats dangerous. Take as example last guy posting about themistor tables right on this forum, he just resorted at trying different tables in firmware and chose one that seemed to fit. Next one doing that will get a roof temp that masks higher temps. May get more confusion than protection.
The lowering of pullup value is to be credited to Gen7 Research page, there explains why its better, mostly better for higher temperatures. Pullup change also changes the 22R drop, and if x2 for each themistor leg, thats even more voltage drop. Idd not much for 4k7, but gains with lower value, 1k or 560 pullup.
Im all in for adding features, i made reprap.org/wiki/RDB that has much of what i think is good, but its diy version and different approach. Still, does have other features even if discussable. Why not get something like that instead. Sry for typos and etc, posting from phone. Done speaking my mind now so cheers.
Let me make a scenario. Ppls copy paste tables, someone copies a not shifted table, that means system gets a maximum value after which all higher temps wont produce higher readings coz voltage cant decrease any lower. For examples this with a non-shifted table will read a max temp of say 250C and when temp will be 350, it will still be read as 250C. Why am i only one thinking thats dangerous. Take as example last guy posting about themistor tables right on this forum, he just resorted at trying different tables in firmware and chose one that seemed to fit. Next one doing that will get a roof temp that masks higher temps. May get more confusion than protection.
The lowering of pullup value is to be credited to Gen7 Research page, there explains why its better, mostly better for higher temperatures. Pullup change also changes the 22R drop, and if x2 for each themistor leg, thats even more voltage drop. Idd not much for 4k7, but gains with lower value, 1k or 560 pullup.
Im all in for adding features, i made reprap.org/wiki/RDB that has much of what i think is good, but its diy version and different approach. Still, does have other features even if discussable. Why not get something like that instead. Sry for typos and etc, posting from phone. Done speaking my mind now so cheers.