Topic | How to get Thermocouple Temp from Log file

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    • #13876 Reply
      Jim
      Guest

      I logged temperature data when I was brewing. I used a K type thermocouple in a brew kettle which is ambient temp (~80°f). Then I ramped up to 155°F for an hour and a half, then to a full boil (it read 213.5°ish) for another hour and a half, then it began to cool. I mention this so you have an idea what the values should calculate out to.

      The Log file provides Aux Voltage DC, and Internal Temperature. On the app there is a math channel and it displays °F. So ultimately I’m looking for the math which takes the Aux Voltage DC and the Internal Temperature to output °F.

      I provided a link to the raw .csv log file. If that’s of any help feel free to view it.

    • #13877 Reply
      Anonymous
      Guest
    • #13878 Reply
      Anonymous
      Guest

      Basically, if you arent somekind of math prodigy, you are screwed :D

      James has said that he used this: https://www.omega.com/temperature/Z/pdf/z198-201.pdf
      for his calculations on app side.

      Here is about same information in little bit easier to copy/paste to your spreadsheet:
      http://www.keysight.com/upload/cmc_upload/All/5306OSKR-MXD-5501-040107_2.htm

      I have used hours to figure that out and at some point, thought it was easier to just learn java and i checked mooshimeter-app sources to see how James did it.. And he had used some shortcuts, i was way deeper in that shit at that point :D (nist instruction says that we need to calculate reference temp to volts, then Vref+Vmeasured gives real temperature. I’m still planning to graph how much difference there is, but its already somewhat close in apps math channel)

      And googling for those conversions gives about 20 different ways to do it, but every time it seems to have same origins at nist ( http://srdata.nist.gov/its90/download/download.html ). And almost every time, something has been lost and to get even close to desired values, they have had to add some “little” multiplications like x1000000 to their functions :D Surprisingly many sites have identical math for volts to celcius conversion, but instructions have randomly millivolts and microvolts in them.. And my head hurts, so i try to avoid thermocouples for few days ;D

      So, its likely that no one really knows how to do k-type thermocouple measurements :D

    • #13881 Reply
      admin
      Keymaster

      Hi Ville and Jim,

      I am putting together a google doc spreadsheet showing how to make the calculation. More soon…

      ~James

    • #13882 Reply
      admin
      Keymaster

      Hi Ville and Jim,

      Here is the spreadsheet Jim provided, but with an extra column of K type thermocouple calculation according to Omega’s formula.

      https://docs.google.com/spreadsheets/d/1Wey1yYsqR3FEac6GPkxgeghpMWvc4Z8sH21Yz7ZlQdc/edit?usp=sharing

      Jim – I am sorry to report that I think the thermocouple was not properly connected during this experiment… it looks like the aux input voltage didn’t rise in a way that matches your description of temperature change. If you provide more details on the setup I am happy to try and help.

      Feel free to use this spreadsheet as a template, I also gave commenting permissions to anybody who sees the link.

      Best
      ~James

    • #13886 Reply
      Anonymous
      Guest

      James,

      You’re awesome! Thanks for taking the time to enter in the table and the formula. I was able to put the temperature in °F and the data looked good. If you look at the chart in the spreadsheet I have a link for below you’ll see it is mostly how I described it.

      I failed to say that every once in a while I raised the bag of grains (just like you would with a tea bag when brewing a cup of tea) to let the malty goodness seep out of the grains. When I raised the grains up, the water level dropped and the thermocouple was in the air causing a dip in temperature.

      https://docs.google.com/spreadsheets/d/1pYjnnupgzOrKRQulTpRkg7-AHwTLs18bVJ-1AXcPlQY/edit?usp=sharing

      I used the Mooshimeter along with the following to collect the data
      Thermocouple $3.85 https://www.amazon.com/gp/product/B00843IKWK/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

      Thermocouple Adapter Connector (5 pack for $5.13)

      Thermocouple to Fluke Adapter ($29.99)

      I’ve been wanting to data-log the temperature aspect of my brewing process for about a year. The Mooshimeter is the right tool (along with the items listed above). Thanks for taking the time to convert the .csv file to a useful spreadsheet. Thanks so much!

      Regards,
      Jim

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