1. a_s_impressed

    Thread Starter New Member

    Jul 1, 2008
    8
    0
    What happens if the input to the A/D module has a negative range before the positive range in concern?

    e.g, I have a signal conditioning circuit converting the reading of a sensor to a range of: -6 to 5V. I'm only concerned with the values 0-5V.

    How will the negative range affect the A/D operation? or shall I eliminate the negative range. And how?
     
  2. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    You can damage the A/D on the PIC.
     
  3. a_s_impressed

    Thread Starter New Member

    Jul 1, 2008
    8
    0
    That's what I thought of. so, do you have anu suggestions to eliminate that unwanted negative range?
     
  4. nanovate

    Distinguished Member

    May 7, 2007
    665
    1
    diode in series with the output
     
  5. a_s_impressed

    Thread Starter New Member

    Jul 1, 2008
    8
    0
    I have tried this too but didn't work. The diode showed a strange response. When it's connected to -0.5 for example the output was around 2.5V . I have the 1N4007
     
  6. Reshma

    Active Member

    Mar 11, 2007
    54
    0
    Have you configured the ADC in the bipolar mode?
     
  7. theamber

    Active Member

    Jun 13, 2008
    318
    0
    You can try with Zener diodes or Schottky diodes but the dynamic range of the ADC may be reduced if you care.
    I am sure that Reshma may have a better answer than this she is really cool.
     
  8. calebsmyth

    New Member

    Jul 15, 2008
    1
    0
    I have 7 years experience with this part,...and 2 years experience with dsPIC33FJ256GP506, do you still require help with this problem ?
     
Loading...