SHT_75 with picbasic pro


Results 1 to 20 of 20

Threaded View

  1. #7
    Join Date
    Feb 2006
    Location
    Gilroy, CA
    Posts
    1,530


    Did you find this post helpful? Yes | No

    Default

    Here is some code for the SHT11 for calculating dewpoint. I have not compared datasheets to know how similar (or not) they are. But this may help:

    http://www.picbasic.co.uk/forum/show...=3851#post3851

    That is quite the equation! From NavMicroSystems post above:
    Code:
    '** Dewpoint Calculation
        ' See: SENSIRION Application Note "Dewpoint Calculation"
        ' logEW = (0.66077+7.5*T/(237.3+T)+(log(RH)-2)
          ' DP = ((0.66077-logEW)*237.3)/(logEW-8.16077)
    
    DewPoint:
      
      TempDP=Temp/10
      logEW=6608
      sign=TempDP.bit15
      wz=ABS TempDP
      wx=(7*wz)+(wz/2)                              
      wy=2373+wz
      wj=wx/wy
       For ix=15 to 0 step -1
        wx=(wx//wy)<<1
        wz.bit0(ix)=wx/wy
       Next
      wx=(-sign^((wj*10000)+(wz**10000)))+sign        
      logEW=wx+logEW
      wx=RHtc
      wj=(NCD wx) - 1
      wx=wx<<(15-wj)
      wz=0
      For ix=14 to 0 step -1
        wy=wx**wx
        wz.bit0(ix)=wy.bit15
        bt=~wy.bit15
        wx=(wy<
       Next
      
      wx=((wj*4000)**49321)+(wz**6021)
      logEW=wx+logEW-30000            
      sign=logEW.bit15
      logEW=(-sign^(((ABS logEW)+2)/4))+sign
      wx=1652-logEW
      sign=~wx.bit15
      wx=ABS wx
      wy=20402-logEW
      wj=wx/wy
      
       For ix=15 to 0 step -1
        wx=(wx//wy)<<1
        wz.bit0(ix)=wx/wy
       Next
      
      DP=((23730**wz)+5)/10
      DP=(-sign^DP)+sign
    And attached is an application note for dew point calculations.
    Attached Images Attached Images
    Last edited by ScaleRobotics; - 29th November 2010 at 15:21.
    http://www.scalerobotics.com

Members who have read this thread : 0

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts