PT 100 3 interfacing

Discussion in 'Embedded Systems and Microcontrollers' started by anujab9, May 16, 2008.

  1. anujab9

    Thread Starter New Member

    May 16, 2008
    4
    0
    Hello All,

    I want to interface the PT 100 to meshnetics module(Zigbee wireless platform).
    This module has inbuilt ADC.
    Its 3 wire PT100
    The temperature range is -20 ºC to 400 ºC.
    Right now I am using Wheatstone bridge with INA326 instrumentation amplifier.
    This works well with Range of 0ºC to 400 ºC
    So, What changes should I made to measure negative temperature?

    Regards,
    Anujaa
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Can you state the problem you are having? Is the signal from the INA a problem? We would need a schematic to have some idea of the circuit.
     
  3. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
  4. anujab9

    Thread Starter New Member

    May 16, 2008
    4
    0
    Hello
    its just interconnection of brige and instrumentation amplifier
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    You won't be able to read negative temperature directly with a single supply amplifier. You'll either need an old-fashioned dual supply amp or you'll need to offset the output from your bridge.
     
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