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Topic: Trouble with 31855K Thermocouple  (Read 725 times) previous topic - next topic

saud

Hi,
I am new to Arduino and just received my 31855 board and Set it up as described here
http://henrysbench.capnfatz.com/henrys-bench/max31855-arduino-k-thermocouple-sensor-manual-and-tutorial/

The output I am getting is attached. The internal temp reads OK. The sensor is at room temperature. There are 3 problems
1) readings are negative,
2) reading are unstable
3) readings are inaccurate

I can't figure out what I have done wrong. I have checked my connections.


outsider

Just remember at normal temperatures the red wire is negative on most thermocouple types, type K is red and yellow. Don't know if that helps but its something to check first.

saud

Thanks for your reply. I have a green and a white wire. I have tried connecting both ways but the three issues I mentioned remain the same. Only difference is that the temperature starts to decrease when heated on reversing the connections.

I have seen people recommending 'grounding' the Arduino to help with the fluctuation but I don't understand how I would go about doing that.

saud

OK, I got it to work!
Added a 0.01uF capacitor across the thermocouple connectors and all the problems vanished.

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