DS18B20 data in excel

[tim griff]

Hi

I'm OK with the PICAXE code to handle the data output from a DS18B20 and display correctly on my display.

I then transer the data via a datalogger into MS Excel spreadsheet.

What I cannot work out is how to handle the "sign bit" in the spreadsheet ie positive or negative numbers .............. any thoughts

Regards
Tim

 

[hippy]

Not familiar with Excel but if you're using ReadTemp's 8-bit data, an equation for all cells in the temperature column/row like the following should do it ...

  ' Input value = 0..255
  If inputValue >= 128 Then
    outputValue = -(inputValue-128)
  Else
    outputValue = inputValue
  End If

If using ReadTemp12 12-bits ...

  ' Input value = 0..4095
  If inputValue >= 2048 Then
    outputValue = (inputValue-4096) / 16
  Else
    outputValue = inputValue / 16
  End If

 

[tim griff]

hippy,

Thanks, I understand this now.
I had

let w1 = w1 ^$ffff + 1

in the code to handle negative values............. it was this that was "masking" the true value from the sensor which I need in the datalogger.

Cheers