Topic | Bug in Thermocouple calculation

Home Forums Mooshimeter Support Bug in Thermocouple calculation

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    • #9407 Reply
      Sebastian G.
      Guest

      Hi
      thanks for this usefull Funktion but there seems to be a bug in the calculation.
      Mine is showing Temperature in °C and up to 3mV it shows 100°C fine (25°C internal Temp)
      4mV 133°C should be 123°C
      5mV 183°C should be 150°C
      6mV 237°C should be 170°C
      7mV 323°C should be 195°C
      8mV 455°C
      9mV 641°C
      10mV 804°C
      10.8mV 1135°C should be 290°C

      so it shows at the tip of my soldering iron 800°C…

      http://www.lkmelectronic.de/deutsch/downloads/pdf/Typ-K.pdf

      Thanks
      Sebastian

    • #9413 Reply
      admin
      Keymaster

      Hi Sebastian,

      I just ran a test and my readings agree with yours, and on analysis I agree that the issue is in the conversion from voltage to temperature.

      I based the calculations off of this document:
      https://www.omega.com/temperature/Z/pdf/z198-201.pdf

      Now looking at the implementation and found the issue. The conversion leaves off the top few terms of the polynomial, and the error agrees with your measurements almost exactly. You can see the calculation here:

      https://docs.google.com/spreadsheets/d/1eg4aHukD8bJAVI7HQQ6azENjBmrJ2hzh4joTsvCcNHY/edit?usp=sharing

      So thank you for this, I’ll put the correction in the next beta release. I’d like to send you a coupon code as a thank you, can I use the email address you commented with?

      Best
      ~James

    • #9417 Reply
      Anonymous
      Guest

      Yes, may email adress is correct

      Thanks
      Sebastian

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