Thermocouple Voltage

Discussion in 'General Electronics Chat' started by emilj726, Jul 23, 2014.

  1. emilj726

    Thread Starter Active Member

    Oct 1, 2010
    52
    2
    Does anyone know if an thermocoupler's voltage can be scaled with a voltage divider. I have a K-type and I want to scale the voltage. as an example when the temperature is at 275 C and the voltage is 10mV I want to scale that in half to 5mV. Is that possible?

    Thanks
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    sure..
    but why?
    Do you not have some sort of calibration on the device the TC is attached to?
     
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,999
    745
    You can use an opamp and alter the gain with a resistor divider, or use an AD595 thermocouple amp and adjust the gain.
     
  4. emilj726

    Thread Starter Active Member

    Oct 1, 2010
    52
    2
    I have attached a sketch of what I am going to do. A1+ and A1- are going into a PLC. The reason why i want to scale the voltage is because the plc is rated to read temperatures at high as 300 C. So basically I just want to fool the plc so that I can go as high as 400 C. Since I am dividing the voltage in half with the resistors externally, in the plc program I will basically double whatever value the plc is reading so i can display accurate values.
     
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    dont forgetr to keep the wire types the same, each junction will generate a bit of voltage with disimilar metals.
     
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