• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 1188 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LIQUID LEVEL SENSOR using FDC1004

Suresh Kumar
Prodigy 110 points
Other Parts Discussed in Thread: FDC1004

Hi everyone, 

              We are using FDC1004 for liquid level measurement,  Actually for us every femto farad is very much impotant. End result depends on a capacitance(fF). If capacitance varies End result also vary. So how to achive the 1 femto Farad accuracy. Now in femtofard level i achieved  the first  two digits are stable and third digit have little variation but  fourth digit have more variation.

EXample:  9.5304pF it will be 9530fF in this 95 will be constant and 30 will be varying, how to stable the last two digits. 

              End  application is completed, if  liquid level measurement is completed then we will move to production.

             Anyone can please suggest how to resolve this issue.

Thanks & Regards

Suresh Kumar.S

              

    

  • 0
    TI__Expert 7400 points
    Hi Suresh:

    The best way to reduce the noise is by making your CDC measurement rate to be 100SPS on the FDC1004. This is give an inherent noise resolution of 0.5fF rms -> ~3fF peak to peak. The Out of Phase liquid level approach will help with robustness against any parasitic capacitance in the surrounding area.

    Thanks
    -David Wang
    Capacitive Sensing Application
  • 0 in reply to David Wang11
    Prodigy 110 points

    Hi Mr.David,

    Thanks for your reply. Presently i am using 100SPS only.  Actually we are using separate boards for FDC1004 and controller, So we are using some wires for connecting FDC1004 and sensor probe as well as FDC1004 to controller. I hope if i get actual PCB their i can get good accuracy better than this. As soon as possible i will get the actual PCB their i will check the accuracy and i will share with you.