Tempetature control of a wire

Discussion in 'General Electronics Chat' started by alexis damianidis, May 17, 2015.

  1. alexis damianidis

    Thread Starter New Member

    May 17, 2015
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    Hey,
    I would like to know how I can determine and control the temperature of a wire at a specific point of temperature.
    I want to control the temperature from 100-300 celcius.
    This can been achieved from the ampere load of the wire?
    Or please send me your opinion of how it can done in a different way
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Are you using Nichrome wire (at that temperature, you better be)?
     
  3. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    Yes! And I've done it to a high degree of accuracy (within 1C up to 1000C for a *very* small piece of platinum wire).

    The trick is to alternate between 'heating' and 'measuring' very quickly (faster than the thermal time constant of the wire). Use a high current voltage source for heating, and a precision low current source for measuring. You may need to use a "Kelvin" connection to eliminate errors due to connection resistance. And, the resistance vs. temperature curve may not be linear for the wire material. A lookup table solves this.
     
  4. alexis damianidis

    Thread Starter New Member

    May 17, 2015
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    You mean you managed to control the wire temperature from 1c to 1000c?
    I want to control the temperature of a wire kanthal wire or Pure Nickel Wire Ni200 (NON RESISTANCE)
    I want to control through a source MOSFET that is capable to variably change the voltage to a specific current,so as to increase the temperature to a specific point that is from 100-300c
    Can you be more specific?Sorry but me English are not the best
     
  5. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    No. The wire temperature (via resistance) was measured, and controlled, between room temperature and 1000C with a resolution of 1C (and an accuracy of about 5 to 10C).

    My approach used a PWM operating about 20khz. The on (heating times) were about 4 to 10 uS. The measurement was made during the off times.

    A PID algorithm was used to maintain the temperature (via adjusting the PWM on time) at a given set point in approximately 1C increments.

    This was all driven via a PIC MCU.
     
  6. alexis damianidis

    Thread Starter New Member

    May 17, 2015
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    Thanks a lot for your quick reply.
    Do you sell the PID algorithm I am very interested.
    I want to do exactly the same thing.
    Can you pm me?
     
  7. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    No...I don't sell my code. I'm just here to give you ideas...
     
  8. alexis damianidis

    Thread Starter New Member

    May 17, 2015
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    Sorry I did not want to insult you my apologies.I just work on this project a long time now and I am really confused.
    But you have helped me a lot with your answers.
     
  9. alexis damianidis

    Thread Starter New Member

    May 17, 2015
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    I am sure my electronic engineer and friend will come up to somenthing with this idea
     
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