MAX31850K 1-wire reading only ‘nan’

hi i have a problem reading the value from MAX31850K.
No matter how I plug it in, I have the answer

Device Address: 3B419D8409C82CA0 Temp C: nan Temp F: nan

I am using modified onewire and dallas temp libraries from the website Grove - 1-Wire Thermocouple Amplifier(MAX31850K) - Seeed Wiki
It is connected directly to Arduino Leonardo, with 4.7k pullup resistor between vcc-data lines, but I also tried without it. Seems like it works in parasite power because it still answers ‘nan’ even with VCC disconnected.
I have several other DS18B20 sensors and they all work like a charm.
I also tried it on other 1-wire library and it worked but only up to 255C - when temperature was above it read -127 like it was disconnected. (I’m aware that DS18B20 only work to 125C so thats the reason).
please advice :slight_smile:
I now tried on Arduino MEGA 2560 and its exacly same.

Post a link to the thermocouple you connected!

Post a link to the breakout board you're using (I doubt that you soldered a TDFN case manually)!

The library you linked to checks the fault bit in the result and shows NAN if the chip detected a faulty thermocouple. Maybe that "other" library doesn't check that bit and simply displays a possibly wrong value.

Yes I it was not clear in my previous post but I am using Grove module from seedstudio to which I posted a link:

Thats excatly the board I have.
I connect it to Arduino. Tried Leonardo and Mega 2560.

I am using a basic automotive thermocouple bought locally. Dedicated for EGT sensors, there's really not much specs about it, only that it's Type K, and works in 0 to 1200*C range.

Well the official not modified onewire and dallastemp libraries show value up to 255*C so I suspect they only read 1 byte, while MAX31850K stores data on 2 bytes, am I right?
I do not have the possibility tu check the accuracy of the temps it shows but it seems reasonable.

The library for DS18B20 sensors doesn't check the fault bit because these sensors doesn't have such a bit (the sensor element is internal). You can modify the above linked library to ignore the fault bit if you think that the values are valid anyways.

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