180°C sensor with 2°C sensitivity

Discussion in 'The Projects Forum' started by drago, Feb 23, 2011.

  1. drago

    Thread Starter Member

    Aug 12, 2009
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    I need to built a circuit similar to this

    http://forum.allaboutcircuits.com/showthread.php?t=43391

    but on higher temperature and much more accurate.

    For me problem is how to start! What sensor to use that is reliable at 180°C for long period of time and accurate.

    Circuit is used in machine for producing PVC tubes in chamber where temperature must be regulated in 2°C with fans and blowers.

    If you guys help me to start and chose a right sensor other part of circuit how to power on the fans is not a problem. Fans which are DC i will use mosfet to power them on and for AC i will use relay.
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. drago

    Thread Starter Member

    Aug 12, 2009
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  4. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,348
  5. drago

    Thread Starter Member

    Aug 12, 2009
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  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Figure 4 at that page will give you an amplified signal:

    [​IMG]

    The output could be used to feed the circuit from the circut you showed in your first post.

    Bertus
     
  7. drago

    Thread Starter Member

    Aug 12, 2009
    14
    0
    max4237/4237 are high-precision op amps and i can't find them in RS Components store.
    Can you suggest me a alternative that is available in RS?

    Yes!figure 4 is a basic amplifier with added positive feedback through R2. This will add me more precision to drive a comparator

    Bertus you are a hero!
     
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