RaceDAC analog channel & K-type thermocouple

I have got my raceDAC set up and working for my NTC and other analog inputs it's working OK
Now I want to monitor exhaust gas temperature so using K type thermocouple on a spare analog input.
However, I am not seeing any results with change of temperature, the K type thermocouple has polarised inputs.
What's the proper way to connect thermocouple to RaceDAC ??

Comments

  • Hi, please ask RaceDAC directly. They follow this forum regularly and here's other knowledgeable users too, but as it's 100% RaceDAC question, I'm sure you'll get fastest answer directly from them :)
  • Hi donic,

    https://en.wikipedia.org/wiki/Thermocouple#Type_K
    Type K (chromel – alumel) is the most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C.

    That is 41 microvolts per celsius degree. That is why you need an amplifier which boosts the signal level to 0-5 000 millivolts or 0-15 000 millivolts; which are the measuring ranges of RaceDAC.

    A couple of examples/ You can use RaceDAC +5V output to power up these:
    http://www.adafruit.com/products/1778
    http://www.adafruit.com/products/269

  • Great, I understand the reason now. ..
    Thank you for the information and the links to the prebuilt modules - this has been very helpful to me.
    As I am using 2 stroke engine, the EGT measurement is an important tuning factor..
    I looked in the RaceDAC documentation, but no reference to any thermocouple typical connection example.
    Consideration, perhaps for future RaceDAC documentation inclusion.
    Thanks again !! :)
  • For example this one:
    http://www.adafruit.com/products/1778
    On the left: + and -, to thermocouple
    On the right:
    V+ is the power input, connect to RaceDAC +5V
    GND and GND, to RaceDAC GND
    OUT is the analog signal, to analog input in RaceDAC


    Forget the second one:
    http://www.adafruit.com/products/269
    It needs SPI data interface.
  • Yes I see.. the AD8495 thermocouple amplifier IC - it's the perfect solution, small and easy - would be nice if the RaceDAC had thermocouple amplifier (maybe jumper selectable input or similar) option on-board PCB, future hardware revision? who knows.
    For the time being it's not a problem, I ordered some of the AD8495 pre-built modules it's easy to wire, I just need to make it strong to withstand vibration etc on racing bike.
    Thank you for creating RaceDAC and Racechrono !!
  • edited July 2015
    Thank aol for creating RaceChrono.

    We have created only the RaceDAC.
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