My K-type thermocouple (grounded enclosure type) connected to MAX31855 adapter connected to Arduino Mega gives me faults every few readings. It's really, really bad. I've tried swapping thermocouples, adapters, and Arduino's in various permutations and reached the conclusion that this happens whenever the thermocouple sheath/shielding touches the metal frame I've got the rest of my contraption set up on. Also gives faults when I touch it. Works perfectly fine when floating or completely isolated from everything else.
I've tried connecting myself to ground, and I've tried connecting the frame to ground, but nothing works. What should I do? I thought this was the whole purpose of the shielding. :(
When I check continuity on the probe, I get 3 ohms between probe tip and one lead and 7 ohms between probe tip and other lead. This is exactly the same for another thermocouple I've tried. No surprise here, as it's a grounded type enclosure thermocouple.